Battle robotic clones to save the planet! Invader Zim has a sinister plot to overtake Earth. In this action-packed side-scroller, you"ll do battle as SpongeBob, Danny Phantom or El Tigre. Harness their special powers and your math skills to defeat the forces of evil. And, you can customize the game online with the math skills you"re studying in school. For use with the Didj Custom Gaming System, sold separately.