One-hit KO

This article or section is incomplete. You can help SmashWiki by expanding or finishing it. The editor who added this tag elaborates: Needs some more info from Ultimate

For the smasher OHKO, see Okoru.

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.

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.
• Knockback may be insufficient to KO at 0% on very large stages (e.g. Temple, New Pork City, and 75m), or from the far edge of a stage.
• Knockback may be insufficient to KO at 0% if the attack had already been landed previously (due to stale-move negation).
• Knockback may be insufficient to KO heavy characters at 0%.
• 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.

Trivia

• The Home-Run Bat is the only item able to perform a guaranteed OHKO in every Smashgame.
• Marth's Critical Hit is the only Final Smash to mantain its OHKO power in every installment. In Brawl, it is also the most powerful playable attack ever of the Smash serie, without any external buff.
• Tabuu on Intense Difficulty in the Subspace Emissary has more OHKOs than every other boss or enemy in all the "Smash" games: even 10, beating Galleom's 5 in Brawl and Master Hand's + Crazy Hand's 5 + 2 in both Melee and Brawl. Tabuu's OHKOs are reduced to 8 on Intense difficulty in Boss Battle, also 2 of them are not always guaranteed anymore, needing sweetspot. Several other Tabuu's attacks are an invariable KO as low as 20% on higher difficulties.
• Tabuu's Off Waves or touching Winged Tabuu on Intense Difficulty in the Subspace Emissary and Boss Battle are the most powerful OHKO attack in every Smash game, both for damage (over 100% to 200%) and immense knockback. The Ultimate Chimera's bite in Brawl also inflicts enormous knockback and 100% or 200% damage (if sweetspotted).
• In Brawl only, a few attacks have such enormous knockback to be a guaranteed OHKO even on Super Mushroom characters. Examples include Suicune's Aurora Beam, Lugia's Aeroblast, Marth's Critical Hit, Ultimate Chimera's bite and several enemy or boss attacks. Occasionally characters powered by Metal Box may be OHKOed, but it is rare and not guaranteed. Marth's Critical Hit will always OHKO a Super Mushroom Bowser on the very large stage New Pork City.
• Starting from Brawl, the most powerful attack of the final boss is usually a OHKO and features Waves in some form or fashion. These include the infamous Winged Tabuu's Off Waves (the most powerful attack ever), Master Core's Blast Waves (similar to the previous but much less strong and slower) and Galeem's Lens Flare (this one not always a OHKO).

References

This video illustrates several OHKOs from all Smash games:

• Some Final Smashes in Brawl:

https://m.youtube.com/watch?v=M1NebBaQ8ow

• Some Poké Balls in Melee:

https://m.youtube.com/watch?v=gx_wE6R8L_E

• Some Poké Balls in Brawl:

https://m.youtube.com/watch?v=pNOnc_7cRqE

• Other Poké Balls in Brawl:

https://m.youtube.com/watch?v=-2TZyw8-oRE

• Some Assist Trophies in Brawl:

https://m.youtube.com/watch?v=eJBhgB8-_qI

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 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). Touching Lugia’s body can also lead to a OHKO if multiple hits chain.
• Articuno’s Sheer Cold (sweetspot).
• A thrown Polar Bear.

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).
• Master Hand’s Flying Slap.
• Crazy Hand’s Fake-Out Slap.
• Crazy Hand’s Power Punch.
• Master Hand and Crazy Hand’s Crush (if all hits connect).
• Master Hand’s and Crazy Hand Flying Punch (sweetspot).
• Master Hand’s and Crazy Hand’s Jestream (sweetspot).
• Combined Master Hand’s and Crazy Hand’s Applause (if all hits connect).
• Combined Master Hand’s and Crazy Hand’s Sandwich Punch.

Others

In Cruel Melee, several 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 and kicks. 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, 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, most of Tabuu's moves are guaranteed OHKOs in every situation, some of them even in the higher difficulties of Boss Battle (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 PK Flash) 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.

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] (SSBB)|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. It is also the most powerful player attack of all Smash games in term of knockback, without any exterior factors or buffs.
• 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). 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 all 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 all hits connect.
• Olimar's End of Day if all hits connect (bury, ascent, and explosion). Offstage opponents hit by the rocket's thrusters will also experience an 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. 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 invariably OHKO.
• 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.
• Knuckle Joe's Vulcan Jab to Rising Break attack.
• Dr. Wright’s highest skyscraper.
• Lyn’s slash (sweetspot).
• 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.
• If a Pitfall is thrown on a flying character, he will be meteor smashed with a OHKO potential if he is midair.
• 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.
• 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.

Stage hazards

• The Ultimate Chimera's bite on New Pork City.
• Dialga's Roar of Time and Overheat and Palkia's Spacial Rend on Spear Pillar.
• The three fastest versions of Sidesteppers and Shellcreepers on Mario Bros., or every version when smash thrown. Touching the green Flames is a OHKO for most characters.
• Corneria's laser beams.
• Touching the hull of the Pirate Ship.
• 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:

• Big Primid's and other Primids' punch.
• The forward smash of all four R.O.B.s.
• Armight's double blade attack.
• Auroros's flying attack.
• Big Goomba' charge.
• Bytan's full power charge (at low health).
• Feyesh's sparkling slash.
• Gamyga's laser beam (both complete and incomplete form).
• Touching Glice, Glire and Glunder.
• Roturret's projectiles.
• Shellpod' charge (both armored and non-armor form).
• Spaak's thunder.
• Towtow's charge.
• The most powerful attacks of Shadow Clones, such as forward smash and up smash.

The following will cause a OHKO on both Very Hard and Intense difficulties:

• Armank's main attack.
• Autolance's slash.
• Touching a Bombed.
• Floow's mind attack (if most hits connect or at full health).
• Giant Bytan's full power charge (at low 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 are also capable of OHKOs.

The Subspace Army (bosses)

The following will usually cause a OHKO on Intense difficulty only:

• Rayquaza's Blast at low health (25%).
• Rayquaza's Lightning Strike if most hits connect or at low health (25%).
• Porky Minch's Lightning (if most hits connect).
• Ridley's Background Ram (sweetspot).
• Ridley’s Slamming Rush.
• Duon's Jump Crash.
• Duon's Vacuum Spin (if most hits connect).
• Galleom's Shockwave (first hit only).
• Galleom's Uppercut.
• Tabuu's Explosive Teleport (randomly).
• Tabuu's Rapid Chop if most hits connect (final slash only).
• Touching Tabuu through Electrical Shield.
• Tabuu's Shark Blade.

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 Sword Blast (the hit itself, not the shockwave).
• Meta Ridley’s Mega Fire Ball.
• Galleom's Tank Rush and Slam (only used by Tank Galleom at very low health).
• Galleom's Falling Body Slam.
• Galleom's Tornado Spin (if most hits connect).
• Tabuu's Pinpoint Explosion.
• Tabuu's Bullet Rain (second attack).

The following will cause a OHKO on Hard or higher difficulties:

• Tabuu's Golden Bracket. Due to perfectly horizontal knockback, this attack is a guaranteed OHKO for poor recovery characters even on Easy difficulty.
• Tabuu's Dragon Laser.
• Tabuu's Chain of Light. When two players fight, Tabuu will attempt to smash them together with the Chain, resulting in a potential double OHKO.

The following will cause a OHKO on Normal or higher difficulties:

• Tabuu's Off Waves or touching Winged Tabuu (invariable).

The following will cause a OHKO on every difficulty:

• Porky Minch's Energy Laser if most hits connect or Porky has low health (25%).
• Meta Ridley’s Falcon Flyer Smash.
• Meta Ridley’s Falcon Flyer Stamp.
• Tabuu's Off Waves or touching Winged Tabuu (sweetspot).

Meta Ridley's Falcon Flyer Pull on every difficulty is not a OHKO in conventional terms, since it simply pulls the player beyond the bottom blast line, KOing regardless of damage. The only way to survive it is jumping.

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).
• Master Hand’s Flying Slap.
• Crazy Hand’s Fake-Out Slap.
• Crazy Hand’s Power Punch.
• Master Hand and Crazy Hand’s Crush (if most hits connect).
• Master Hand’s and Crazy Hand Flying Punch (sweetspot).
• Master Hand’s and Crazy Hand’s Jestream (sweetspot).
• Combined Master Hand’s and Crazy Hand’s Sandwich Punch (invariable).

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).
• Combined Master Hand’s and Crazy Hand’s Sandwich Punch (sweetspot).

Boss Battle (bosses)

The following will usually cause a OHKO on Intense difficulty only:

• Duon's Sword Blast (sweetspot; the hit itself, not the shockwave).
• Meta Ridley’s Mega Fire Ball (sweetspot).
• Galleom's Tank Rush and Slam (sweetspot; only used by Tank Galleom at very low health).
• Galleom's Falling Body Slam (sweetspot).
• Galleom's Tornado Spin (if most hits connect).
• Tabuu's Chain of Light. When two players fight, Tabuu will attempt to smash them together with the Chain, resulting in a potential double OHKO.
• Touching Tabuu through Electrical Shield (sweetspot).
• Tabuu's Shark Blade (sweetspot).
• Tabuu's Pinpoint Explosion.
• Tabuu's 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%).
• Tabuu's Golden Bracket. Due to perfectly horizontal knockback, this attack is a guaranteed OHKO for poor recovery characters even on Normal difficulty.
• Tabuu's Dragon Laser.

The following will cause a OHKO on Hard or higher difficulties:

• Tabuu's Off Waves or touching Winged Tabuu (invariable).

The following will cause a OHKO on Normal or higher difficulties:

• Tabuu's Off Waves or touching Winged Tabuu (sweetspot).

The following will cause a OHKO on every difficulty:

• Meta Ridley’s Falcon Flyer Smash.
• Meta Ridley’s Falcon Flyer Stamp.

Meta Ridley's Falcon Flyer Pull on every difficulty is not a OHKO in conventional terms, since it simply pulls the player beyond the bottom blast line, KOing regardless of damage. The only way to survive it is jumping.

Other bosses' attacks are also capable of OHKOs.

Others

In Cruel Brawl, several 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 and kicks. Each of the Alloys has 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. The same strengthening, or maybe a bit less, was already seen in Melee.

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, even to a character as light as Jigglypuff, KOing it only 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

• Giga Mac's fully charged Straight Lunge sweetspot, fully charged up smash when sweetspotted, 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 can carry players past the upper blast line, but as they inflict no knockback they are not considered one-hit KOs. Both 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

• Master Core's final Waves if the player does not defeat it in time (about 45 seconds).
• Master Core’s final explosion after unleashing the Waves (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 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.
• R.O.B.'s fully-charged Gyro will OHKO opponents beyond its maximum speed. However, it requires a much stronger windboxes consecutively at the gyro making it extremely difficult to achieve its power. [1]

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.

Hero's Whack with Thwack are actually instant KOs despite them commonly (and incorrectly) being considered one-hit KOs, as they KO opponents regardless of position. This also applies to any Final Smash that ends with opponents bursting on the spot in a colorful explosion.

Final Smashes

• Marth and Lucina's Critical Hit.
• Lucario's Aura Storm at max aura.
• Donkey Kong's Jungle Rush at max rage.
• Little Mac's Giga Mac Rush at max rage.
• 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.
• Zero Suit Samus's Zero Laser if all hits connect (barely in OHKO threshold, easily DIed by holding towards the stage).

Items/Enemies

• A smash attack with the Home-Run Bat.
• Electrode's explosion when smash thrown.
• The Dragoon.
• The Daybreak (sweetspot).
• 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

• Galeem's Lens Flare with weaker or no spirits (sweetspot; 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: