Patrick's alter ego in "Survival of the Idiots"; he argues he is in fact Dirty Dan. He is not; SpongeBob is. Also he makes the awesomest face when he asks "Who you callin' Pinhead?"
Wasn't Pinhead Larry the second toughest outlaw in history?
One who lacks the intelligence of the "normal" sector of the human population; even so cannot handle the most mundane of tasks due to the lack of common sense and intelligence.
Some one who has a small head for their body size. Also can be characterised by a small jaw and/or large ears. Obviously, some one with a small head, receeding jaw and large ears can be described as "piphead extremis".
While watching the TV we noticed that the presenter was a Piphead. The more we looked the more obvious it became.