A moron who is full of shit. Usually someone who professes to be an expert at everything, but in reality 1) knows very little, 2) has completely incorrect information, or 3) knows of nothing of interest to others (drivel). However, regardless of their lack of knowledge or of pertinent information, they feel compelled to talk ad nauseam about their selected topics. They usually find themselves to be an expert at just about everything.
"You are totally full of crap, you shitron." "Don't listen to Bob, he's a shitron, everything he'll tell you is wrong."