Trianglehead is friends with Longneck Noneck. He has a small body and a large, triangle-shaped head, hence his name.
How does he even lift that thing off the ground?
Many people ask this, but it's obvious he has invisible flying turtles lifting his head. Most giant headed people have turtles, like pops, from regular show. Except, trianglehead has a smaller body and his head is 108497395734587340985738957349587% bigger than in the photo, so it takes 190463653475864358634783756345633766666666666674378588888888888888839465 turtles to lift his head.