The Banana Peel, otherwise known as the Banana is an item that has been in every installment in the Mario Kart franchise. When obtaining this item through the Item Roulette, you can either throw it infront of you or hold it behind you and then drop it. When another racer runs into a Banana Peel, in complete cartoon fashion, they spin out. If you wish to use these in a defensive fashion, you may hold the banana behind you, and if a Red Shell comes trailing behind you, the Banana Peel will offer complete protection from the incoming obstacle. The Banana Peel is the most common item in the game, and probably the least affective, but hitting just one can make the difference of you being 1st place... and 2nd...
The Banana Bunch is an item that has exclusively appeared in Mario Kart 64. It comes in the form of a Banana Bunch consitsting of five Bananas that you drop one at a time. If a fellow racer bumps into the Banana Bunch you were holding behind you, all the Bananas will shoot out in all different directions. In Mario Kart DS, Mario Kart Wii, and in Mario Kart 8, the Banana Bunch appears, but instead as the "Triple Bananas" which trail behind you in the DS and Wii versions. However in Mario Kart 8 the bananas will spin in a circle around you.