Superman was in a battle with Doomsday, during the fight the collision they caused accidentally caused a portal between the two alternate universes. Bananaman and Crow get into the portal. Bananaman saw Superman being nearly killed by Doomsday. Bananaman kills Doomsday after a hard fought battle. But Superman got cosmic radiation from the collision so he sees Bananaman as Doomsday. And they fight each other.
Morals off for Bananaman not Superman
Battle ends in death or KO
Battle takes place in Asgard
Crow can help Bananaman in the fight and has unlimited supply of bananas and indestructible