Mr. Butlertron is the loyal robot servant and best friend/roommate to Principal Scudworth. He is programmed with a highly sensitive compassion protocol (a parody of Mr. Belvedere).
As a far more obvious allusion to Mr. Belvedere, Mr. Butlertron was initially named "Mr. Belvetron", and lines were recorded with him being called by this name, but it was eventually changed due to legal reasons. However, the premiere Canadian broadcast occurred far before the American premiere and before legal issues arose (or at least before anything could be done about them), and so this original intended name did see airtime. Dialogue calling him by this name was re-edited around episode 3, although by that time his name was mostly shortened to Mr. B, so the change did not seem so out of place.
Nonetheless, one of the bonus features on the DVD release shows Phil Lord performing lines as Principal Scudworth from episode 7, "Plane Crazy: Gate Expectations", referencing to Mr. B as "Mr. Belvetron". As production on episodes of television shows, especially animated series, normally occurs weeks if not months before their original broadcast, it is not strange that the name was still in use by the production team as late as the 7th episode. Although, it was never broadcast with the line in this form.
Voiced by Christopher Miller. Mr. Butlertron's voice is extremely metallic and monotonous, and he usually only has two intonations: a regular robotic voice, and a slightly deeper variant he uses at the end of sentences. He will often speak in his regular voice and then switch to his deeper voice at the end to call whoever he's addressing "Wesley". One exception to this is in Escape to Beer Mountain: A Rope of Sand when he uses a higher than normal intonation, seen again in Makeover, Makeover, Makeover: The Makeover Episode.
Though he is usually polite and laidback, he does have a temper which came out when had a fight with Scangrade and when he showed jealousy towards Ecybo Pooch. He is Principal Scudworth's loyal butler, as well as Clone High's vice principal and dehumidifier. He is the voice of reason in a situation and tells others what the right course of action is.
- Mr. Butlertron calls everyone "Wesley", a reference to the youngest son on Mr. Belvedere, Wesley Owens.
- Mr. Butlertron is shown without his mustache in a photograph taken in the 80s in the opening to the show.
- He also has chest hair and armpit hair as shown when he took off his red cardigan sweater vest.
- It is suggested in "A.D.D.: the Last D is for Disorder", that his compassion and approachable nature comes from his "magic" red cardigan. This, however was just Scudworth's stupid theory, as it really comes from his obvious nice attitude.