Banana Peel (move)
The Banana Peel is Diddy Kong's Down B move where he tosses a Banana Peel the opposite direction he's facing. This move can be either be used like a tilt or like a smash; the former will make the Banana Peel come out at a shorter arc, while the latter causes a much higher arc. Diddy can pick up Banana Peels from the ground and throw them for a small amount of damage and a slip. Additionally, if another character walks, runs, or rolls over a Banana Peel (or lands on top of one), they will slip and fall, and the Peel will move away from them a bit. This goes for every character except for Charizard and Meta Knight while dashing, since they hover above the ground over banana peels while doing so. Since these Banana Peels are owned by Diddy, he cannot be tripped up by them unless someone else picks them up. Only two Banana Peels can be in play for each Diddy Kong. If a Diddy tries to use this move with two Banana Peels on the field already, Diddy will go on with the animation but another banana will not come out. Diddy can pick up a Banana Peel while cartwheeling with his dash attack. Diddy can also Glide Toss his Banana Peels, among with many other Advanced Techniques.
Origin
Bananas were collectables from the game Donkey Kong Country. They functioned exactly the same as coins from the Mario series, as if a player collects 100, s/he will gain an extra life. There were even banana bunches that have ten of them.
In Donkey Kong 64 there were banana peels on the floor in Donkey Kong's tree house, and if he (or any other kongs) walk over them, they'll slip, but not trip and fall on the floor. Bananas as collectables are alot more important, as there are 100 colored bananas (each representing a different kong (yellow for Donkey Kong, red for Diddy Kong, blue for Lankey Kong, pink for Tiny Kong and green for Chunkey Kong) in each world (except the final world, Hideout Helm) which are neccisary for accessing boss battles. There were also the Golden Bananas, giant bananas that have a gold color which act simillar to the Power Stars from Super Mario 64, as they are required to unlock more levels. Though they could simply be the same banana peels from the Mario Kart series. It could simply be inspired by the fact that Diddy Kong, as a monkey, loves bananas.