The Overbearing Know-It-All is an ignorance demon. He only appears in the movie, not in the book.
Description[]
He has spindly legs but a huge, round body and is mostly mouth. He often falls on people and hurts them, and provides misinformation on every subject. In the film, he meets his demise when Milo plugs his mouth with the word "humility" and the buildup of bad advice causes him to inflate like a balloon and explode.