Guy wakes up to find a gorilla is on his roof, so he looks in the phone book and finds an ad for "Gorilla Removers". He calls the number, and the gorilla remover says he’ll be there in 30 minutes.
The gorilla remover arrives and gets out of his van. He's got a ladder, a baseball bat, a shotgun and a dog.
"What are you going to do?", the homeowner asks.
The gorilla removal expert says, “I'm going to put up this ladder against the roof, then I'm going to go up there and knock the gorilla off the roof with the bat. When the gorilla falls off, the dog is trained to bite and hold the gorilla by the balls until I get down and slap on the handcuffs.” Then he hands the shotgun to the homeowner.
Homeowner asks, "What's the shotgun for?"
"If the gorilla knocks ME off the roof, shoot the dog."