Mike

Mike is a teenager who participated in the "Big Brother/Big Sister" program in Elwood City. His only main appearance is in "Buster's New Friend" but he makes a few cameo appearances in other episodes. Mike was Buster's volunteer brother, because his mom said that he needed "older male influence". He is extremely interesting, is good at minigolf, is able to spin the ball in bowling, and can drive a car. Arthur and the others were jealous of him at first because they thought that Mike was around their age and was just another friend. Arthur in particular didn't like Mike because he was keeping Buster busy instead of with his other friends, but eventually came to like him, asking if he knew anything about magnets for their report. He has only appeared once and it is unknown if he and/or Buster are still in the Big Brother/Big Sister program. He makes a cameo in the episode Revenge of the Chip as he is seen waiting in line to see You Do The Most Embarrassing Things Live at Wonderworld.

Physical appearance
Mike is a bear with a light brown complexion and long brown hair combed forward. He wears blue jeans and a denim jacket over a white T-shirt that says "Big Brother". In Elwood City Turns 100! he appears in the crowd during the musical, but he is now shown with blond hair—it's possible that he dyed it.

Arthur

 * 11302. Buster's New Friend
 * 30502. Revenge of the Chip (Cameo)
 * 70500. Elwood City Turns 100! (Cameo)
 * 91002. Breezy Listening Blues (Cameo)
 * 140201. The Agent of Change (Cameo)
 * 200602. Mutiny on the Pitch (Cameo)

Postcards from Buster

 * 137. Coming Together (Cameo)

Books

 * Buster's New Friend