Sidesteppers emerge from the pipes on the upper portion of the stages and move from one side to the other. They can be defeated either by being hit from below or being turned upside-down by the POW Block, after which they can be kicked off-screen. Sidesteppers, however, are resilient, as the player would need to hit them from below twice; however, they become faster if they are hit only once.
If the Sidesteppers are not defeated while flipped upside down, they flip upright and become irritable, after which they change color and move faster.
Sidesteppers also appear in the Mario Kart series as obstacles in certain courses.
In Super Smash Bros. Brawl
As a stage hazard
Sidesteppers appear as a stage element in the Mario Bros. stage. They are stage hazards, but they can be attacked or hit by the stage's POW Block, at which point they flip upside down and become throwable items. As items they can also be hit to send them flying: weak attacks like jabs or Fox's Blaster launching them a short distance and strong attacks will launch them very far.
Sidesteppers like the other enemies in the stage, cause very large horizontal knockback, whether or not they are thrown. Due to the odd shape and low ceilings of the stage, throwing these enemies is the easiest way of defeating opponents, as there is not enough vertical knockback for them to tech on the ceilings. A flipped-over Sidestepper can be eaten by Munchlax.
Similar to their behavior in the original game, each time a Sidestepper is left on its back for long enough, it will get up again, will change color (from red to blue to purple), and move faster. Different colored Sidesteppers don't have any differences when hit or when used as an item.
In Smash Tour
Sidesteppers appear as a red trophy item. When used, the player's fighter will have the speed of their sideways dodges increased for the duration of that battle.
The Sidesteppers trophy appears as part of the Mario Bros. Trophy Box.
In Super Smash Bros. Ultimate
As a stage hazard
Sidesteppers return as a stage hazard in the returning Mario Bros. stage. Their behavior when walking around is unchanged, however how knockback affects them has been changed. In Brawl any attack was able to flip a Sidestepper and launch them, now they receive knockback similar to characters and need some amount of knockback to flip. This prevents things like Fox's Blaster or Bayonetta's Bullet Arts from protecting themselves from Sidesteppers or having a low-commitment method of launching them at opponents. Low knockback attacks like Falco's Blaster can still flip them, but they will need to be picked up and thrown or hit with a stronger attack to be of any offensive use.
The Sidestepper also appears as a Novice-class support spirit.
In Adventure Mode: World of Light, the Sidestepper is presumably one of the countless spirits captured by Galeem during his takeover of the universe. The Sidestepper's spirit is located in the 8-bit maze section of The Light Realm.
The Sidestepper's Spirit Battle uses an army of Mr. Game & Watch puppet fighters and is fought on he Mario Bros. stage. During the battle, after defeating the first three red Mr. Game & Watch puppet fighters, four blue Mr. Game & Watch puppet fighters appear with increased move speed, referencing how the Sidesteppers can turn blue and increase their speed when damaged. The last four red Mr. Game & Watch puppet fighters also appear and deals damage by dashing into the player's fighter, referencing the angered Sidesteppers attack by dashing into the player.
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