Crackpot Category Theorist

Then there was the crackpot category theoretician who thought he was a catamorphism operation. He'd walk around the psych ward with a pair of bananas, which he'd hold up around the other patients and giggle maniacally. Once he did this to the resident hypochondriac (of inoperable brain cancer), but it didn't seem to bother him. "What are you doing?" he asked.

"I'm constructing a unique arrow," said the crackpot, "with YOU as its target!"

"So what's the big deal about that?" said the hypochondriac. "I'm terminal." (Of course, this joke is only funny if the mental hospital is Cartesian Closed...)