Sonic Gather Battle

Sonic Gather Battle is a fan game based on the Sonic the Hedgehog series, featuring characters from Super Mario Bros, Mega Man X, and Bleach. It uses the Little Fighter MD-2 game engine and is a mix of arcade beat-em-up and multiplayer game. The game is best known for it's inclusion of a trojan. Not all of its effects are currently known, but it contains DRM that performs malicious actions to afflicted computers and makes the game itself unplayable. The game's creator apparently put the malicious code into the game to prevent people from ripping sprites from it, despite his attempts, these sprites were ripped and sent to the internet.