- “Bad Bananas - they may sound like an indie band but it's actually the source of Rabbid Kong's newfound powers. Rabbid Kong has minions stockpiling them for him everywhere. We have no choice but to destroy the Bad Bananas on sight.”
- —Beep-0, Mario + Rabbids Kingdom Battle
Bad Bananas are Bananas corrupted with the Megabug's power seen in the Donkey Kong Adventure mode of Mario + Rabbids Kingdom Battle. Originally normal bananas before falling into the Megabug Pool, they eventually corrupted Rabbid Kong when he ate one of them, giving him immense power and psychotropic behavior. He then ordered other Rabbids to stockpile this new power for him.
Bad Banana piles are stage obstacles in some of the game's levels; they do not affect the gameplay on their own, but all Bad Banana piles in a single level must be destroyed in order for Donkey Kong and co. to proceed.
After the group defeats Mega Rabbid Kong in battle, all of the Bad Bananas turn back into normal Bananas, causing Rabbid Kong to revert to normal.