Skullmonkeys may be primitive in their actions, but we shouldn't forget that they have lots of machinery that can blast your head off. Robot Hover Monkeys are one of those, and they're unbuttbouncable, too!
Made for being guards they usually hover above the ground peacefully, unloading a pink laser ball from time to time that bounces into all directions after hitting the ground. If you don't dodge it in time you're toast.
They can be found at the Science Center and in Evil Engine #9.