From IvanWiki

Bananas leave peels when eaten, and can be zapped for no effect whatsoever. Bananas can also be broken, which does nothing.A special variant of the banana is the Golden Banana, which is only worth more, and nothing else. There is also The Holy Banana of Oily Orpiv.

Peels

Banana peels are the leftovers of eaten bananas, and can hurt you when you slip on one. Hedgehogs and spiders, sometimes even kobolds, die from this happening to them.