This is a person that is pretty much a sarcastic asshole and/or a slightly balding fuck. They try to make you laugh by tellin terrible jokes about some dead guy that nobody gives a flyin fuck about in the first place. They cant stop talking about needless things in life.
Q: Hey i am trying to think of a description for Mr. Griffin. Can you help me?
A: Yeah man thats easy. He is That Guy.
Q: Isn't that kinda harsh?
A: Nah man he meets the description perfectly.
Trinite's are as a whole "that guy"