A Literal Dickhead

Listen up, simpleton. The joke here is a pun on the insult 'dickhead'. The person in the picture has a bald head with a specific indentation that makes it look like the head of a penis. So, while 'dickhead' is usually just a mean word, in this case, it literally describes the shape of their head. You probably don't even get how funny that is, you simple bear-like person.