It acts vaguely like a Motion-Sensor Bomb, although its purpose is to stun rather than damage and knockback. It can be thrown like any other regular item, and when someone else steps on it, they fall over and are temporarily stunned. The banana itself flies a short distance sideways, just far enough that if the slipper rolls the wrong way, they will slip again. Diddy Kong's Down Special Move generates Banana Peels even with items turned off, which is an important strategy in tournaments because it often disrupts an opponent's ground game, forcing them into the air. Unlike Banana Peels in the Mario Kart series, these peels do not have faces on them, and do not affect the paths of racing Shy Guys on the Mario Circuit stage.
The peel from a Japanese fiber banana of the Musaceae plant family. It contains a high volume of vegetable oil, which oozes out when the peel is stepped on, making things slippery. In Smash Bros., the peel fulfills its destiny as a comedic prop by making passersby slip. Characters who land on their backsides will be defenseless until they recover their footing.
Super Mario Kart (1992)
Mario Kart 64 (1997)
The Banana Peel also appears as a sticker in Super Smash Bros. Brawl, under the simple name banana. When used in the Subspace Emissary, it adds +4 to Flame Attacks.
In Super Smash Bros. 3DS/Wii U
The Banana Peel returns in Super Smash Bros. 3DS/Wii U, and just like in Brawl, it causes pratfalling. However, there is one major dfference: the banana will disappear after it trips one opponent, instead of hanging around to trip multiple opponents. This is most likely due to the effort made by the Smash Bros. team to prevent the prevalence of pratfalling.
Looks like someone had a nice snack and didn't bother to clean up afterward... As you may suspect, stepping on a banana peel sends you falling to the ground and exposes you to attack. You can throw these at your opponents too, but please clean up when you're done, all right?
Tripping in SSBB almost looks identical to when a character slips on a banana peel.