After he, Jimmy and Jimmy's big brother Bill are rescued by Supercar - following their private plane's emergency ditching in the sea - Mitch immediately proceeds to make himself right-to-home in the secret Nevada laboratory...up to, and including, Supercar's launch bay (!), prompting amused test pilot Mike Mercury to observe, "I think we've found a co-pilot!"
He's definitely chief mischief-maker of the place - apt to pop up most anywhere, from Dr. Beaker's laboratory to Professor Popkiss' kitchen and even Mike's bedroom, gamely stirring up (usually) good-natured trouble...and with a gift for being in the wrong place at the right time, for his human friends!
Mitch was voiced (eek-eek and all!) by David Graham.
- Mitch was inspired by a pet monkey Sylvia Anderson's parents owned when she was a child.
- According to series lore, to prepare for his role voicing Mitch, Graham spent a day observing monkeys at the Monkey House at the London Zoo!