Invader Zim #23
There's a virus in GIR's head. This virus is mean, determined, and probably covered in spikes and stuff. Most importrantly, it's making GIR want to kill ZIM, and ZIM can't really let that happen. But the only way to destroy the virus is to travel inside GIR's broken robot mind, and the inside of GIR's broken robot mind is a virtual madhouse of crazy.
PART TWO OF A FOUR-PART STORY!