Gorilla with a Machine Gun

What is big, black, and hairy? It's a gorilla with a machine gun.

Explanation

Explain Bear

Alright listen up, genius. This joke is funny because it subverts your expectations. You thinkin' 'bout some kinda animal, right? But BAM! It's a gorilla... with a MACHINE GUN. Bet you didn't see that comin', did ya? You probably wear velcro shoes and think dinosaurs are still alive.