Monkey Dude is a Badnik from the video game Sonic the Hedgehog 3, residing in the "Angel Island Zone". Since this Zone doesn't exist within Sonic the Comic, it perhaps isn't surprising that Monkey Dude hasn't yet appeared in an STC story. It's only appearance is in the Sonic's World feature of the first Sonic the Summer Special.
Similar to the Coconuts Badnik from the Emerald Hill Zone, Monkey Dude waits in a tree and attempts to attack passers-by with a well-aimed coconut. The advantage Monkey Dude has over its predecessor is its longer arm, giving it the chance to attack assailants further away. The huge drawback is that Monkey Dude only holds one coconut, so is totally vulnerable to attack once it has dispensed of its weapon.