The Mountain Maniac is the titular antagonist of the Adult Swim video-game "Mountain Maniac" - which has the player take on the role of a psychotic stereotypical lumberjack armed with a large mallet, who becomes posssessed by uncontrollable rage and begins to attack nearby cities via using his mallet to send boulders crashing down on the nearby cityscapes.

As the Mountain Maniac continues his rampage varied obstacles get in his way such as police, SWAT teams and even the army - all of which he somehow fights off as he continues to cause mayhem across varied levels - moving from mountain to mountain, slaughtering everything in his path in a comically over-the-top fashion.

The Mountain Maniac also returns in an X-Mas special, where he has been working as a mall Santa following the end of the original game (part of his community service) - only to once again go insane, this time trying to kill Santa himself (ironically, while dresses as a mall Santa): fighting many of Santa's helpers and reindeer while also destroying Festive themed cities with the aid of his ever-trusty mallet.