Guy wakes up and there's a gorilla on the roof. "Why is there a gorilla on my roof?" he asks. There is no answer, because this joke has a minimalist cast. Anyway he calls an animal removal service and asks for a specialist.
The specialist arrives. He is an expert at getting gorillas off roofs. He has a bunch of bananas, a Rottweiler, and a gun.
"Here's what I'll do," the man says. "I'm gonna go up with these bananas, try to distract him long enough to push him off the roof. When that happens the dog will run up and bite his balls off. That'll take the fight out of the gorilla."
"I see. But what is the gun for?"
"That's for you," the man says. "If I'm the one falling off the roof, you shoot the dog."