Stage hazard

A stage hazard is any aspect of a stage (that is, a stage element) which could pose a threat to players. Most stage hazards deal damage and knockback while the remainder include a wide range of effects such as sudden movements of the stage or a panning camera that can carry less agile characters into the blast line. A stage hazard should not be mistaken for any element which might aid or save the opponent, such as the Support Ghost in Yoshi's Island, although the same element may play several roles.

How predictable a stage hazard is and how much influence it has over the match are factors usually considered when deciding stage legality. Stages with many or overwhelming hazards are typically banned in tournaments as they tend to interfere with the outcomes of matches or because the competitors only value aspects of a match that they have control over.

Some stage hazards may be extremely minute or subtle, or only apply to certain characters; For example, the balloon in Smashville may unexpectedly collide with Ness's PK Thunder, making him temporarily vulnerable or leaving him in the helpless state if he is in the air.

Stage hazards often play a role in improvised combos.

Types of stage hazards

• Static hazards generally stay in place or follow a set path and produce damage and knockback upon collision. Examples of stationary static hazards include spikes and the bumpers on Peach's Castle, and an example of a moving static hazard includes the minecart in PictoChat. Some static hazards have a fixed knockback. Static hazards that cause damage but not knockback or flinching include hoop damage and the rain in the Kitty Cover mini-game on WarioWare, Inc.
• Blast hazards will appear and fire or explode over a period of time, entrapping players that come near their radius. The damage they inflict depends on how long the character remains trapped within the blast. Some blast hazards will seek a target before executing, such as the Combo Cannon on Halberd, while some will appear randomly, such as Banzai Bill in Princess Peach's Castle.
• Launchers will quickly move the character from one part of the stage to another and sometimes into the blast line. The most basic example of a launcher is the catapult on Pirate Ship which will only fling the victim to the far left of the pirate ship while the victim suffers neither damage nor flinching. The Barrel Cannon in Congo Jungle is considered a launcher but not usually a hazard because there is a brief period of time where the player has control over when it will fire.
• Rogue platforms are platforms that travel or move suddenly move through a blast line. For example, if a character is stunned while standing on an Arwing in Sector Z, the Arwing may leave the scene and carry the character into the blast line. The track on Big Blue and balancing platforms on Mushroom Kingdom may also be considered rogue platforms.
• Trapdoors are sections of the stage that can give way and reappear over a character, which usually makes returning to the stage difficult or impossible. For example, King Bulblin on the Bridge of Eldin can destroy the bridge and players can be trapped below when the bridge is later reconstructed. Another example of a trapdoor hazard is the Drop Block in one of the default custom stages in Brawl.
• Transformations create a situation where the character can be caught under or off to the side of a stage because of a sudden shift in the stage. For example, the Frigate Orpheon stage can cause players to accidentally self-destruct when it flips upside down. Not to be confused with the trapdoor hazard, as transformation hazards specifically feature a (near) global change in the stage.
• Acid hazards, which do not specifically need to be acid, rise or pour in while covering a blast line. Collision with the acid will result in damage and knockback. In high hitstun and low percentage environments, characters will sometimes bounce around in rising acid. The first stage to feature an acid hazard is Planet Zebes. Norfair features lava in the place of acid.
• Predators will pursue the players and attack them. Some examples include the lookout cannons on Pirate Ship and the Arwings and Wolfen which swoop in and fire lasers around characters on various Star Fox stages.
• Vehicles may occasionally speed through some stages, causing damage and knockback to characters that collide with them. A warning or environment cue that a vehicle is approaching is usually given, such as a flashing exclamation point on Onett, or the vehicle can be seen from far away before arrival, such as the racers on Mario Circuit. Vehicles collisions may also trigger explosions on certain items.
• Weather hazards affect physics. These hazards typically follow a change in scenery or a stage transformation; For example, the Flying transformation in Pokémon Stadium 2 introduces a weather hazard that blows gusts of wind upwards. Characters caught in the gusts have a dramatically reduced falling speed and are easier to Star KO and approach. Other weather hazards may affect the progression of time, such as Dialga in Spear Pillar.
• Slippery platforms make it difficult to control the momentum of traversing characters. Slippery platforms may also increase the odds a character will trip. This hazard does not affect the Ice Climbers.
• Switches need to be activated before any changes occur. Currently, the only switch that significantly threatens players is the [POW Block] in Mushroom Kingdom.
• Panning cameras force characters to follow the camera as blast lines will move with the camera. Icicle Mountain features a camera that pans up the stage at varying speeds, which can catch characters with the lower blast line if they have poor jumping ability.
• Obstacles generally obstruct character movement or present a challenging gap to cross. While not dangerous by themselves, obstacles are often used in conjunction with panning cameras.
• Illusions are designed to affect the players themselves rather than the character, although they can sometimes lead to disorientation and self-destruction. Palkia on Spear Pillar can tilt the screen's orientation of the stage and invert player controls by mirroring the stage.
• Enemies generally appear as a species and can obstruct the player or cause knockback and damage. Enemies are similar to static hazards, but most enemies can be defeated or can be grabbed and thrown. One example of an enemy hazard is the Polar Bear in Icicle Mountain.
• Monsters are large enemy species that cannot be defeated and can KO a player when hit, grabbed, or swallowed by. Some monsters include the Ultimate Chimera on New Pork City and the fish on Summit.