Guy walks in a bar, sees a dude with a head the size of a grapefruit. "Not to be nosy, but why is your head so small?"
Well, I'm a fisherman, and I had been out on the water for weeks with nothing to show for it, when I suddenly caught a mermaid. She begged and pleaded for me to release her, she could grant me any wish I wanted! I'd been out for weeks, so I thought, what the hell--How about we have sex?
She laughed, I'm scales from the waist down!
So.......I asked her for a little head.