Monster Party

Monster Party is one of the strangest and most memorable platformers on the NES (Dendy), released by Bandai in 1989.

An ordinary boy named Mark meets Bert, a winged creature from Dark World, who asks for help. Mark goes to the other world with his baseball bat, hits enemies and their projectiles back at them and fights bizarre bosses, from a giant shrimp tempura to a dead caterpillar. When he eats a capsule, Mark merges with Bert and can fly and shoot.

It is a cult horror comedy platformer.