Swamp Thing is an unreleased Sega Mega Drive game based on the DC comic book series of the same name. It was developed by Microsmiths and had it been released, the game would have been published by Nuvision Entertainment.

A prototype of the game was dumped by SegaAge in November 2010. It depicts the game as a sidescroller where you play as Swamp Thing hitting enemies. You also have the ability to transform into nearby objects such as logs. Unfortunately there is only one music track used throughout the entire game, and due to the stiff controls the game is very difficult.