Knock knock / Who’s there? / Gorilla

Knock knock
Who’s there?
Gorilla
Gorilla who
Gorilla me a hamburger

Here is another bad knock-knock joke. The humor in this one comes from the punchline. A gorilla might be reasonably able to knock on a door, so though they can't talk, the setup is fairly plausible.

The punchline uses gorilla as a pun for grill, which is a major stretch, so the pun is a bad one.