Caterpillar: "Hey sister, what do you call a dog with three heads?"

Dormouse: "I don't know.  What do you call a dog with three heads?"

Caterpillar: "Forrest."

Dormouse: " ...  I don't get it."

Caterpillar: "Yeah, I don't really get it either."

Dormouse: "Well, where did you hear that joke?"

Caterpillar: "I made it up."