Mario pulls out a cape and swings it in front of him, reflecting projectiles and reversing hit characters. The cape starts to reflect projectiles at the frame 6. This also applies to Dr. Mario with his Super Sheet. The cape has a multiplier of 1.5× when a projectile is reflected.
The cape can flip shielding opponents. Also, the cape will briefly reverse an opponent's momentum (not in Super Smash Bros. Melee). Shortly after an opponent is flipped in the opposite direction, if they make a directional input such as a forward roll, they will instead roll backwards. This seems to affect most (including buffered) inputs made while being caped. This also does not work in Melee.
Mario's Cape deals up to 10% damage, dealing no knockback and doesn't make opponents flinch except for in Melee when used on an opponent attempting a grab, which deals slight knockback. Characters hit with the cape while attempting a grab will be sent spiraling a short height into the air. This means that it will not interrupt attacks; rather, it only turns the enemy character around, leaving their hitbox active. It can leave recovering characters unable to grab the ledge. This is less potent in Super Smash Bros. Brawl and Super Smash Bros. 4 due to their differing ledge mechanics, in which characters can grab ledges regardless of which direction they are facing. The cape can be broken in the same manner as any other reflecting attack can; if the damage the oncoming attack can break a shield in one hit, the cape will not work and Mario will be stunned (in Melee) or get hit by the attack (since Brawl). In Super Smash Bros. 4, Mario's Cape can reflect projectiles behind him as it is swung from his back upon use, but it requires timing. The damage has been nerfed over time (10/8 in Melee to 8/6 in Brawl and 7/5 in Smash 4). The move has a sweetspot closer to Mario in Melee and the move is weaker in the air in all games. This move can be B-reversed if the the player has the timing.
If used on someone in Brawl while taking knockback from an attack, it multiplies the distance by about 1.6.
The Cape can also be used for multiple advanced techniques; Cape glide, the Cape Dash (reverse Cape glide), the Cape Boost (Meta Knight insta-kill), Cape Induced Landing Lag, and Edge Cape-cancel. These techniques only work in Brawl.
In Super Smash Bros. Ultimate, the animation is changed aesthetically, as Mario is now wearing the cape around his neck while he swings it. In addition, Cape now forces opponents to show their backside once reversed. Because of that, it is the only way to see the backside of characters with a mirrored stance (such as Mario himself) without using glitches.
Special Move customization was added in Super Smash Bros. 4. These are the variations:
In Super Mario World, the Cape is a power-up obtained from the Cape Feather, which transforms Mario into Cape Mario. While wearing a Cape, Mario can perform a spinning attack, using it to attack enemies and destroy most projectiles. Additionally, by holding the jump button while airborne Mario can slow down his fall. The cape can also be used to fly great distances after a running start: in this state Mario can stay airborne indefinitely by diving and pulling up at regular intervals, which allows him to skip large portions of some levels. The Cape's floating capabilities in its source game could have inspired its ability to stall Mario in midair in Smash Bros.