One-hit KO
A one-hit KO, commonly abbreviated as OHKO (also referred to as an Instant KO in Melee), is an attack in the Super Smash Bros. games with such high base knockback that it KOs an opponent at 0%. Such attacks currently exist in every installment of the series.
Definition
In general, a move is considered a one-hit KO if:
- It is capable of KOing Mario at 0% through sheer knockback alone from the middle of the respective game's Final Destination.
- It is not a meteor smash unless the hitboxes are also capable of OHKOing onstage (meteor smashes like those Beast Ganon are therefore OHKOs, while Luigi's down taunt is not).
- It deals damage and/or does not cause a KO by forcibly re-positioning the opponent (such as push effects and dragging Final Smashes. There are some exceptions, such as Jigglypuff's Puff Up in Brawl which has both sheer OHKO power and an extreme push effect, and Samus' Zero Laser in the same game, which has dragging hits before the final hit).
- It is not extremely situational (such as the first hit of Roy's Blazer against Jigglypuff in Melee, or Jigglypuff's uncommonly high shield jump).
Another common standard is to compare the move's knockback to the smash attack of the Home-Run Bat, one of the few moves intended to be the quintessential OHKO by the developers.
Moves with the potential to OHKO are not necessarily guaranteed to do so, and may fail to OHKO under the following circumstances:
- The opponent techs, DIs, utilizes momentum cancelling, and/or crouch cancels to reduce the knockback or alter the trajectory of the attack.
- The opponent is flung into a wall, which absorbs enough knockback to prevent the OHKO, or successfully executes a wall tech.
- The move's sweetspot does not land (particularly evident for Roy’s Flare Blade in every game featuring him).
- The move requires more hitboxes to land but some of them fail (for example, Lugia’s Aeroblast in Melee, which can whiff if the character is hit on the edge and escapes; in Brawl it deals a single, immensely powerful hit which always OHKOs, but suffers from a smaller hitbox).
- The stage is extremely large (e.g. Temple, New Pork City, and 75m), or the opponent is at the far edge of a stage.
- The move was weakened previously due to stale-move negation.
- Opponents are under an effect that makes them more resilient (such as being giant, metal, or in an event that reduces the knockback they sustain), or the player is weakened (such as being tiny or given a lower handicap).
- The launch rate is lower than standard, reducing knockback.
- The opponent's gravity is affected via equipment.
List of One-Hit KOs
This page lists the moves that can OHKO within the rules mentioned above.
Certain moves and situations are not considered to meet the definition of one-"hit" KO's:
- Moves or hazards that inflict no knockback (for example, being flown off the screen by the Landmaster or eaten by the Summit's Fish or Distant Planet's Bulborb), as they simply move opponents into the blast lines.
- Sacrificial KOs and instant KOs (such as Bowser's Flying Slam or Hero's Whack), as they do not deal any conventional knockback.
- Moves that hit an opponent who is close to a blast line (such as Pikachu's Thunder), as almost any typical attack ingame will be able to KO opponents at that point.
Some stage hazards or enemies are capable of OHKOing on their respective stages, and will be listed below.
In Super Smash Bros.
Moves that KO at 0% were almost nonexistent in the original Smash. In fact, aside from the Home-Run Bat, only one move in the game is able to OHKO, under uncommon conditions:
Items
- A smash attack with the Home-Run Bat.
- If Fox uses Reflector on a walking Bob-omb, he (as well as any character caught in the blast radius) will be OHKO'd.
- If 2 Foxes use Reflector on a Green Shell, it will eventually gain OHKO power after 3-4 reflects.
In Super Smash Bros. Melee
Unlike in Smash 64, there are multiple moves that can OHKO in Melee. They still remain rare, however.
Playable characters' moves
- Roy's almost fully charged or fully charged Flare Blade (sweetspot).
- Mr. Game & Watch's fully loaded Oil Panic after absorbing three strong projectiles (such as three PK Flashes).
- Roy's Counter upon countering an extremely powerful attack (sweetspot); a hitbox that deals around 35% damage will result in an OHKO if countered (such as a smash thrown Bob-omb).
Items/Enemies
- A smash attack with the Home-Run Bat.
- Touching Moltres.
- Getting caught in Lugia's Aeroblast (if most hits connect). Unlike Brawl, Aeroblast requires more hits to KO at 0%, but its hitbox is very large. Touching Lugia’s body can also lead to a OHKO if multiple hits chain.
- Articuno’s Sheer Cold (sweetspot).
- A thrown Polar Bear (sweetspot).
- A Green Shell gains OHKO power when reflected 3 or 4 times by Fox's Reflector.
Marill can push players past the side blast line, but as it inflicts no conventional knockback it is not considered a one-hit KO.
Stage hazards
- Corneria’s laser beams.
- Banzai Bill's explosion on Princess Peach's Castle (if all hits connect).
- On Flat Zone, if a falling tool is launched at enough speed (after either being hit by an extremely powerful attack such as a Home-Run Bat swing, or being launched after receiving enough damage), it will OHKO anyone it slams into.
Bosses
The following will usually cause a OHKO on Very Hard difficulty only:
- Master Hand’s Finger Drill (if all hits connect) and Flying Slap.
- Crazy Hand’s Fake-Out Slap and Power Punch.
- Master Hand and Crazy Hand’s Crush (if all hits connect), Flying Punch (sweetspot), and Jetstream (sweetspot).
- Combined Master Hand’s and Crazy Hand’s Applause (if all hits connect) and Sandwich Punch.
Others
In Cruel Melee, almost all the attacks of the Fighting Wire Frames are powered so much that they can easily OHKO every character. These moves include, for example, forward smash and up smash, but also punches, kicks and other moves. The same strengthening, if not even more, will be seen again in Brawl.
Video
The following video demonstrates nearly all the moves and hazards that KO at 0% in Melee:
In Super Smash Bros. Brawl
Brawl continued the trend of adding several OHKOs into the game, resulting in a huge number of them (especially in The Subspace Emissary). However, the majority are Final Smashes, items (mainly Pokéballs), stage hazards, enemy and boss attacks, with relatively few being standard moves of playable characters. In higher difficulties of The Subspace Emissary (often Very Hard or Intense), several enemy attacks are invariable OHKOs, as well as many boss attacks. Also, nearly all Tabuu's moves are guaranteed OHKOs in every situation, some of them even in the higher difficulties of Boss Battles (where the player has only one life).
Playable characters' standard moves
- Ike's stage 8 Eruption. If Ike gets inhaled by Kirby, the latter's stage 8 Eruption loses its OHKO power (except when reversed or used in midair).
- Mr. Game & Watch's fully loaded Oil Panic after absorbing three strong projectiles (such as three PK Flashes) or a very strong one.
- The following counterattacks:
- Ike's Counter (sword and body hitboxes) upon countering a hitbox that deals at least ~40% damage.
- Marth's Counter (sword and body hitboxes) upon countering a hitbox that deals at least ~45% damage.
- Any counter or reflector upon countering a sufficiently strong attack or projectile, such as Zelda's Phantom Slash or a Green Shell.
Contrary to common belief, Mr. Game & Watch's Judge #9 is not a OHKO, having very high knockback but not quite enough to qualify under the required conditions (it usually KOs Mario starting from 10%). The same applies to Ike's stage 7 Eruption, which can KO Charizard as low as 8% but doesn't respect the general definition.
Final Smashes
- Marth's Critical Hit.
- Jigglypuff's Puff Up both by push and simple contact (the hitbox when Jigglypuff begins deflating has extremely high base knockback in Brawl).
- Ganondorf's Beast Ganon if most hitboxes land (at least one stomp and charge). If a character paralyzed by Beast Ganon is not hit by the charge afterward, they will be inflicted a meteor smash of OHKO power.
- Lucario's Aura Storm at max Aura if most hits connect.
- Zelda's Light Arrow (barely in OHKO threshold, easily DIed).
- Pokémon Trainer's Triple Finish (barely in OHKO threshold).
- Samus' Zero Laser if most hits connect.
- Olimar's End of Day if all hitboxes land (bury, ascent, and explosion). Offstage opponents hit by the rocket's thrusters will also experience a OHKO via meteor smash.
- Wario-Man's fully charged Wario Waft.
Items
- The Dragoon.
- A smash attack with the Home-Run Bat.
- Touching Moltres.
- Lugia's Aeroblast. Unlike Melee, a single hit will OHKO the character (without trapping them), but the attack suffers a smaller hitbox. Touching Lugia’s body can also lead to a OHKO if multiple hits chain.
- Articuno’s Sheer Cold (sweetspot).
- Suicune's Aurora Beam. The beam will not freeze at 0%, but still deals more than enough knockback to OHKO regardless.
- Deoxys's Hyper Beam or touching Deoxys, both the initial hit and the following multi-hitting laser.
- A thrown Bonsly (sweetspot).
- Electrode's Explosion or after being smash thrown.
- Wobbuffet’s Counter when countering a OHKO attack or an hitbox that deals at least ~35% damage.
- Metagross' Earthquake if all hitboxes land (bury, stomp and upward smash). It also has a powerful meteor smash capable to OHKO nearby midair characters.
- Dr. Wright’s highest skyscraper.
- Knuckle Joe's Vulcan Jab to Rising Break attack.
- Lyn’s slash (sweetspot).
- Waluigi's Racket Smash, sweetspotted, if all hitboxes land (bury, multiple stomps and finishing kick or blow). It can also OHKO characters by meteor smash.
- Five Smart Bombs, Bob-ombs or Blast Boxes exploding at the same time.
- If Wario runs over a buried Pitfall while riding on his Wario Bike, he will be sent flying at OHKO power. A thrown Pitfall can also meteor smash midair opponents with OHKO Power.
- When an Hothead reaches its full power for the last seconds (emitting sparks), any contact will be a OHKO. If an uncharged Hothead is hit by a flame-based hitbox that deals over 30% damage (such as Ike’s stage 7-9 Eruption), it will OHKO when smash thrown. Any sparks it gives off while traversing the stage at this strength will also OHKO.
- A Green Shell gains OHKO power when countered 3 or 4 times by a Reflector (for example Fox's). This also applies to Green Shells and Red Shells obtained by defeating a Koopa Troopa in The Subspace Emissary and to Shellcreepers in Mario Bros. stage. Red Koopa Shells are usually more powerful when reflected.
- If a Soccer Ball is launched at enough speed (after either being hit by an extremely powerful attack such as forward smash, a Home Run bat swing, or being launched after receiving enough damage), it will OHKO anyone it slams into.
Kyogre and Piplup can push players past the side blast line, but as they inflict no conventional knockback they are not considered one-hit KOs.
Stage hazards
- The Ultimate Chimera's bite on New Pork City.
- Dialga's Roar of Time and Overheat (or touching Dialga), Palkia's Spacial Rend and Cresselia's Psycho Cut (at full power before fading) on Spear Pillar.
- The fastest forms of Sidesteppers (Red) and Shellcreepers (both Blue and Pink) on Mario Bros., or every other version of them when smash thrown. Touching the green Flames at high speed is also a OHKO.
- Corneria's laser beams.
- Touching the hull of the Pirate Ship.
- Norfair's giant magma wave if all hits connect.
- The bomb on Bridge of Eldin.
- The first and fourth spikes on Rumble Falls (can easily be teched).
The Subspace Army (enemies and clones)
The following will usually cause a OHKO on Intense difficulty only:
- Armight's double blade attack.
- Auroros's flying attack.
- Big Goomba' charge.
- Boom Primid's boomerang.
- Buckot's fire shards (if all hits connect).
- Touching a Bullet Bill.
- Bytan's full power charge (at low health).
- Cymul's rotating blades (if all hits connect; always need the last slash to land for a KO).
- Feyesh's sparkling slash.
- Gamyga's laser beam (both complete and incomplete form).
- Touching Glice, Glire and Glunder.
- Hammer Bro’s headbutt.
- The fiery punch of five Primids (all except Boom Primid and Scope Primid).
- Puppit's slash.
- The forward smash of all four R.O.B.s.
- Roturret's projectiles.
- Shellpod' charge (both armored and non-armor form).
- Spaak's thunderbolt (the dark form).
- Ticken's charge.
- Towtow's charge.
- Several attacks of Shadow Clones and fighters, such as forward smash and up smash, but also punches, kicks and many others. A similar type of strengthening is seen in Cruel Brawl.
The following will cause a OHKO on both Very Hard and Intense difficulties:
- Armank's main attack and electrical sphere.
- Autolance's slash.
- Big Primid's forward smash, fiery punch and kick.
- Touching a Bombed.
- Giant Bytan's full power charge (at low health).
- Floow's mind attack (if most hits connect or at full health).
- Greap's axe.
- Every Nagagog's martial attack (at low health or the last form).
- Roader's charge.
- Every Shaydas' double slash.
- Touching Jyk (all the three forms).
The following will cause a OHKO on Normal or higher difficulties:
- Touching the Porky Statue.
The following will cause a OHKO on every difficulty:
- Multiple Floows' combined mind attack (together, if most hits connect or at full health).
- Scope Primid's most powerful projectile.
Touching a Trowlon on every difficulty is not a OHKO in conventional terms, since it simply carries the player beyond the top blast line, KOing regardless of damage.
Many other enemies and several Shadow Clones or fighters are also capable of OHKOs.
The Subspace Army (bosses)
The following will usually cause a OHKO on Intense difficulty only:
- Petey Piranha's Left or Right Cage Smash immediately after Roar (only used twice per battle when each cage reaches 1/3 HP; always noticed due to the red aura).
- Several of Rayquaza's moves at low health (25% or less):
- Blast.
- Extremespeed if all hits connect (sweetspot).
- Lightning Strike if most hits connect.
- Porky Minch's Lightning (if most hits connect).
- Ridley's Background Ram (sweetspot), Slamming Rush, Loop-de-Loop (if most hits connect) and Tail Swoop (if most hits connect at very low health; always need the last hit to land for a KO).
- Duon's Triple Slash (if most hits connect), Jump Crash and Head Sword Chop.
- Galleom's Uppercut (sweetspot), Shockwave (first hit only), Tank Rush (only used by Tank Galleom at medium to high health) and Stomping Jump.
Meta Ridley's Tail Swoop if most hits connect (always need the last hit to land for a KO).
- Tabuu's Explosive Teleport (blue bursts; red ones KO at 20% or slightly lower) and Ghost Projection.
The following will cause a OHKO on both Very Hard and Intense difficulties:
- Porky Minch's Dash.
- Touching the Porky Bots sent out by Porky Minch.
- Duon's Charge, Sword Blast (the hit itself, not the shockwave), and Vacuum Spin (if most hits connect).
- Meta Ridley’s Mega Fire Ball.
- Galleom's Tank Rush & Slam (only used by Tank Galleom at very low health), Falling Body Slam and Tornado Spin (if most hits connect).
- Tabuu's Shuriken Boomerang (both hits), Shark Blade (blade and Tabuu’s body hitbox), Pinpoint Explosion and Bullet Rain (second attack).
The following will cause a OHKO on Hard or higher difficulties:
- Several of Tabuu's moves:
- Golden Bracket. Due to perfectly horizontal knockback, this attack will also cause a guaranteed KO for poor recovery characters even on Easy difficulty.
- Dragon Laser.
- Chain of Light. If against two players, Tabuu will attempt to smash them together with the Chain, resulting in a potential double OHKO.
- Electrical Shield (sparkles and Tabuu’s body hitbox). Due to perfectly horizontal knockback, this attack will also cause a guaranteed KO for poor recovery characters even on lower difficulties.
The following will cause a OHKO on Normal or higher difficulties:
The following will cause a OHKO on every difficulty:
- Porky Minch's Energy Laser if most hits connect or Porky has low health (25% or less).
- Meta Ridley’s Falcon Flyer Smash and Falcon Flyer Stamp. These attacks can also drag the player beyond the bottom blast line for a guaranteed KO. In any case, the only way to survive is jumping.
- Several of Tabuu's moves:
- Rapid Chop if most hits connect (always need the last slash to land for a KO).
- Off Waves (sweetspot or contact with Winged Tabuu). Even the sourspot always OHKOs on Normal difficulty and above.
Meta Ridley's Falcon Flyer Pull on every difficulty is not a OHKO in conventional terms, since it simply drags the player beyond the bottom blast line for a guaranteed KO. The only way to survive is jumping.
Tabuu's Bullet Rain is always a KO on every difficulty if the player is hit both by the first (high-damaging bullets) and the second attack (explosive sphere). However, since the two attacks are separated by a few seconds interval when the player is free to move, this move can't be considered a OHKO on all difficulties. The same applies to Tabuu's Electrical Shield: on lower difficulties only, when the players touch Tabuu's body they will simply flinch, although they can be sucked in repeatedly by the attack.
Other bosses' attacks are also capable of OHKOs.
Classic Mode (bosses)
The following will usually cause a OHKO on Intense difficulty only:
- Master Hand’s Finger Drill (if most hits connect) and Flying Slap.
- Crazy Hand’s Fake-Out Slap and Power Punch.
- Master Hand and Crazy Hand’s Crush (if most hits connect), Flying Punch (sweetspot), Jetstream (sweetspot) and Sandwich Punch (guaranteed).
The following will cause a OHKO on both Very Hard and Intense difficulties:
- Combined Master Hand’s and Crazy Hand’s Applause (if most hits connect) and Sandwich Punch (sweetspot).
Boss Battles (bosses)
The following will usually cause a OHKO on Intense difficulty only:
- Porky Minch's Dash (sweetspot).
- Duon's Charge (sweetspot), Sword Blast (sweetspot; the hit itself, not the shockwave) and Vacuum Spin (if most hits connect).
- Meta Ridley’s Mega Fire Ball (sweetspot).
- Galleom's Tank Rush & Slam (sweetspot; only used by Tank Galleom at very low health), Falling Body Slam (sweetspot) and Tornado Spin (if most hits connect).
- Tabuu’s Shuriken Boomerang (both hits), Shark Blade (blade and Tabuu’s body hitbox), Pinpoint Explosion and Bullet Rain (second attack).
The following will cause a OHKO on both Very Hard and Intense difficulties:
- Porky Minch's Energy Laser if most hits connect or Porky has low health (25% or less).
- Several of Tabuu's moves:
- Golden Bracket. Due to perfectly horizontal knockback, this attack will also cause a guaranteed KO for poor recovery characters even on Normal difficulty.
- Dragon Laser.
- Chain of Light. If against two players, Tabuu will attempt to smash them together with the Chain, resulting in a potential double OHKO.
- Electrical Shield (sparkles and Tabuu’s body hitbox). Due to perfectly horizontal knockback, this attack will also cause a guaranteed KO for poor recovery characters even on lower difficulties.
The following will cause a OHKO on Hard or higher difficulties:
The following will cause a OHKO on Normal or higher difficulties:
- Several of Tabuu's moves:
- Rapid Chop if most hits connect (always need the last slash to land for a KO).
- Off Waves (sweetspot or contact with Winged Tabuu). Even the sourspot always OHKOs on Hard difficulty and above.
The following will cause a OHKO on every difficulty:
- Meta Ridley’s Falcon Flyer Smash and Falcon Flyer Stamp. These attacks can also drag the player beyond the bottom blast line for a guaranteed KO. In any case, the only way to survive is jumping.
Meta Ridley's Falcon Flyer Pull on every difficulty is not a OHKO in conventional terms, since it simply drags the player beyond the bottom blast line for a guaranteed KO. The only way to survive is jumping.
Tabuu's Bullet Rain is always a KO on every difficulty if the player is hit both by the first (high-damaging bullets) and the second attack (explosive sphere). However, since the two attacks are separated by a few seconds interval when the player is free to move, this move can't be considered a OHKO on all difficulties. The same applies to Tabuu's Electrical Shield: on lower difficulties only, when the player touches Tabuu's body they will simply flinch, although they can be sucked in repeatedly by the attack.
Other bosses' attacks are also capable of OHKOs.
Others
- In the Subspace Emissary, these hazards are a guaranteed OHKO on every difficulty:
- Touching the hull of The Halberd.
- Touching very powerful flames.
- The Sandbag used in the Stadium for Home-Run Contest gains OHKO power when smashed with a very powerful attack (such as Ganondorf's reverse Warlock Punch). However, this item can never be used outside the Stadium.
- In Cruel Brawl, almost all the attacks of the Fighting Alloy Team are powered so much that they can easily OHKO every character. These moves include, for example, forward smash and up smash, but also punches, kicks and a very high number of moves. Each of the Alloys has also more powerful specific attacks, such as kicks for the Blue Alloy or punches for the Red Alloy, which are both a guaranteed OHKO from the center of the stage even for Bowser. A similar type of strengthening (or slightly lower) was seen in Melee. Also the Shadow Clones and fighters battled in the Subspace Emissary are powered up this way on the higher difficulties only.
Video
The following video demonstrates some moves and hazards that KO at 0% in Brawl:
This video shows some other OHKOs, including more boss attacks.
In Super Smash Bros. 4
Like Brawl, SSB4 continues to add OHKOs to the game.
Playable characters' standard moves
- Roy's almost fully charged and fully charged Flare Blade (sweetspot).
- Ike’s Unyelding Blade (sweetspot).
- Mr. Game & Watch's fully loaded Oil Panic after absorbing three medium power projectiles or one very strong one.
- Villager's Pocket after it has absorbed a particularly strong projectile, most notably Timber. Powerful projectiles released by Pocket that can still be reflected will also OHKO, such as Zelda's fully charged Phantom Slash.
- Many other reflectors also share this behaviour, especially Ness's bat.
- The following counterattacks:
- Ike's Smash Counter and Shulk's Power Vision custom moves upon countering a hitbox that deals 30% damage or more.
- Corrin's Counter Surge, Ike and Roy's Counter, and Shulk's Vision upon countering a hitbox that deals 35% damage or more. These counters technically have varying degrees of knockback, but they nevertheless achieve a KO at 0% without DI.
- Mii Swordfighter's Blade Counter upon countering a hitbox that deals 37% damage or more.
- Lucina and Marth's Counter, Little Mac's Slip Counter, and Palutena's Counter upon dealing the 50% damage cap with their counters (this requires countering a hitbox that deals at least ~38.5% damage for Little Mac and Palutena, and at least 40% damage with Lucina and Marth).
Contrary to its name and intention, Little Mac's KO Uppercut does not KO until above about 30% damage. At 0% it falls short of the necessary amount of knockback, KOing a character as light as Jigglypuff at 12%.
Playable characters' moves (with Rage applied)
While the following moves do not, under normal circumstances, guarantee an OHKO state, with Rage they can perform an OHKO:
- Lucario's forward smash, fully charged. Aura and rage stack.
- Ganondorf's reversed aerial Warlock Punch.
- Kirby's Giant Hammer.
Final Smashes
- These Giga Mac's attacks when fully charged and sweetspotted:
- Straight Lunge, up smash and forward smash (when angled up or horizontally).
- Marth and Lucina's Critical Hit.
- Shulk's Chain Attack when boosted with the Hyper Smash Monado Art (Extremely frame-precise, as the final hit must land before the Art expires, as shown in this demonstration video).
- Wario-Man's fully charged Wario Waft.
- Captain Falcon's Blue Falcon (barely in OHKO threshold, easily DIed by holding towards the stage).
Items/Enemies
- The Daybreak (sweetspot).
- The Dragoon.
- A smash attack with the Home-Run Bat.
- Electrode's Explosion after being smash thrown.
- If the Hothead is powered up significantly by a flame-based hitbox (30% total or higher), it will gain OHKO power. Unlike Brawl, Hotheads don't reach full OHKO power automatically for the last seconds.
- If a Soccer Ball is launched at enough speed (after either being hit by an extremely powerful attack such as a Home-Run Bat, or being launched after receiving enough damage), it will OHKO anyone it slams into.
- Smash attacks when boosted by the Black Knight item from Smash Tour, which occasionally turns smash attacks into OHKOs.
The Beetle and Boss Galaga items and Oshawott can carry players past the blast lines, but as they inflict no conventional knockback they are not considered one-hit KOs. The first two can also be easily escaped by button mashing at 0%.
Stage hazards
- Touching the hull of the boat on Wuhu Island.
- Touching the hull of the Pirate Ship.
Other
While it isn't accessible in regular battles, the bomb used in the Target Blast stage apparently has more than enough power to OHKO under normal conditions.
Bosses
The following will usually cause a OHKO on 8.0 or higher difficulties:
- These Master Core's attacks:
- Blast Waves if the player does not defeat it in time (about 45 seconds).
- The final explosion after unleashing the last Blast Wave (sweetspot). However, it can never truly defeat the players as they have already won by the time the hitbox lands.
Video
The following video demonstrates all the moves and attacks that KO at 0% in “Smash 4”:
In Super Smash Bros. Ultimate
Like SSB4, Ultimate continues to add OHKOs to the game. Several characters also gain the ability to instant KO through Final Smashes or special moves; these do not count as OHKOs and belong in its respective page.
Playable characters' moves
- Roy and Chrom's almost fully charged or fully charged Flare Blade (sweetspot).
- Hero's fully charged forward smash if it lands a critical hit.
- The following counterattacks:
- Roy and Chrom's Counter, Joker's Tetrakarn with Arsene, Shulk's Vision with Smash Art, and Mii Brawler's Counter Throw countering a hitbox that deals around 35% damage or more.
- Corrin's Counter Surge and Ike's Counter countering a hitbox dealing around 40% damage or more.
- Marth and Lucina's Counter countering a hitbox dealing around 43% damage or more.
- Any sufficiently strong or repeatedly reflected projectile when reflected.
- Any throwable item under extreme conditions which cause them to move at a very high speed. An example is R.O.B.'s fully-charged Gyro.
Playable characters' moves (with Rage applied)
- Hero's Hatchet Man with Psyche Up and Oomph active.
- Mr. Game & Watch's Oil Panic if absorbed a strong enough projectile like Hero's Kafrizz.
- Mr. Game & Watch's Judge 9.
Final Smashes
- Marth and Lucina's Critical Hit.
- Lucario's Aura Storm at max Aura if all hits connect.
- Olimar's End of Day if it hits a fighter that cannot be buried. End of Day's bury hitbox deals 633.15 units of knockback, more than enough to KO any character on Ultimate's Training Mode Stage.
Items/Enemies
- A smash attack with the Home-Run Bat.
- Electrode's Explosion when smash thrown.
- The Dragoon.
- If the Hothead is powered up significantly by a flame-based hitbox (30% total or higher), it will gain OHKO power. Unlike Brawl, Hotheads don't reach full OHKO power automatically for the last seconds.
Stage hazards
- Touching the hull of the Pirate Ship.
- Touching the hull of the boat on Wuhu Island.
- Getting hit by a Klaptrap on Jungle Japes.
Bosses
The following will usually cause a OHKO on Hard difficulty only:
- Galeem's Lens Flare with weaker or no spirits (sweetspot, if most hits chain; not guaranteed).
Other
While inaccessible in a regular fashion without hacking, the gun found on the Free the Spirit screen's stage is programmed in as its own usable item, inflicting 25% damage with OHKO power. This situation is similar to Smash 4's Target Blast bomb.
Video
The following video demonstrates several of the moves and hazards in Ultimate that inflict enough knockback to KO at 0%, alongside some powerful moves that don't. However, it also includes a few moves and hazards that do not inflict any knockback:
Trivia
- Brawl alone features much more guaranteed OHKOs than all the other four games combined together: more than double.
- The Home-Run Bat is the only item (and by extension, the only attack) able to perform a guaranteed OHKO in every Smash game, at least on its sweetspot.
- Roy’s Flare Blade and Counter are the only moves to maintain their OHKO power in every installment.
- Marth's Critical Hit is the only Final Smash to maintain its OHKO power in every installment. Throughout all games, it is also the most powerful attack of any character's standard moveset (in terms of knockback) without any exterior factors or buffs, being impossible to survive if in sight of a blast line even on the largest stages of each game. In Brawl its strength is even higher.
- While majority of OHKOs will fail to work on characters under the effects of a Super Mushroom or Metal Box, a few attacks have such high knockback that it will still OHKO under these circumstances. Examples (in Brawl only) include Suicune's Aurora Beam, Lugia's Aeroblast, Marth’s Critical Hit, the Ultimate Chimera's bite and several enemy and boss attacks.
- These attacks in Brawl have such immense knockback that it is possible for the main victim(s) to OHKO other opponents by simply knocking into them.
- Starting from Smash 4, a few Final Smashes have hitboxes that negate the effects of such buffs, such as Marth's Critical Hit.
- Tabuu on Intense difficulty in the Subspace Emissary has more OHKOs than every other boss or enemy in all the Smash games, with 13. His OHKOs are reduced to 11 on Intense difficulty in Boss Battles. In particular, Explosive Teleport loses its OHKO power because blue bursts are removed (but the red bursts still KO well below 30%), while Ghost Projection similarly loses power due to it being very difficult to avoid.
- Considering Tabuu has only 16 attacks, 82% of his moveset are potential one-hit KO moves.
- Tabuu's non-OHKO attacks are still very powerful, with Diving Slash being an invariable KO as low as 20% on higher difficulties and Eye Lasers well below 50%.
- Other bosses that have a notable amount of OHKO moves include Galleom in Brawl (with 7), Duon in the same game (with 6) and both Master Hand and Crazy Hand in both Melee and Brawl (with 5 each plus 2 combined). Other bosses in Brawl have 5 or less OHKOs.
- Combined Master Hand and Crazy Hand have access to 12 potential OHKO moves on the highest difficulty of Melee and Brawl, although most of them need sweetspots or multiple hits to connect to KO at 0%. This also results in their combined attacks occasionally being two OHKO moves.
- Every boss in Brawl (10 total) is capable of a OHKO under certain conditions, at least on Intense difficulty in the Subspace Emissary or Classic Mode. In Boss Battles, however, only 5 mantain this power.
- The most powerful boss-related moves in the Smash series are Tabuu's Off Waves (waves and contact with his body) on Intense difficulty in the Subspace Emissary and Boss Battles, and the Ultimate Chimera's bite in Brawl. All these attacks deal 100%-200% and immense knockback. Off Waves are so strong that it OHKOs even on the lower difficulties of the Subspace Emissary (Easy) and Boss Battles (Normal).
- Brawl introduced the trend of "final bosses" having extremely powerful attacks that feature waves in some form, and are usually a OHKO (on higher difficulties only, except for Tabuu). These include Winged Tabuu’s Off Waves, Master Core's Blast Waves and Galeem's Lens Flare.
- Master Core’s final explosion is the only OHKO that never KOs the player, since the battle is already won before the hitboxes land.