He looks like Patrick but is shaped like Plankton. He has Plankton's voice but has Patrick's personality and stupidity.
Role in episode
After trying to arrive back from the mission of going into the Plan B of going into SpongeBob's brain, Plankton accidentally flies into Patrick, who so happens to arrive at the Krusty Krab. Plankton, who at the time is Plankton SquarePants, slowly morphs into Plankton Star.