The Pennsylvania State Trooper was a policeman.
In 1994, he noticed Harry Dunne driving past holding a beer bottle filled with liquid, that unbeknownst to him, was Lloyd Christmas' urine. He asked Harry to pull over a few times before Harry finally got the message and stopped the van. Believing it to be beer, the cop took a swig, and got a nasty surprise.
He was obviously a very corrupt cop, as he drunk what he thought was confiscated alcohol, though it was actually urine. The cop insulted Lloyd, calling him a 'pumpkin-pie haircutted freak'.