Jack Klompus

Jack Klompus was a minor character in the Seinfeld television series. He was played by Sandy Baron and appeared in six episodes.

He was a short tempered resident of the Del Boca Vista condos in Florida and seems to consistently have a grudge against Morty Seinfeld (Jerry's dad).

He carried a Space Pen which could write upside-down. He showed it around and gave it to Jerry after the comedian character complimented it, leading to consternation over whether it was a gift that should have been accepted.

Klompus claims to have ridden in a Cadillac before, "hundreds of times... thousands".