The Idiot is seen in Boxman: Drawing Madness and he was the main anagonist in that game. He is not seen in later games but he is seen in Boxman: Origins as a younger bully. He is not seen after that, which means he is possibly dead.
He is 15 years old but in Boxman: Origins, he's only 13.
He is actually 3 inches but in his massive size after the chemical, he was around 20 inches tall making him almost a metre.