Robot Plankton

Robot Plankton is the hidden true main antagonist of the 2003 videogame SpongeBob Squarepants in Battle for Bikini Bottom (mainly its console versions). He is a giant robotic version of Plankton. He and SpongeBot SteelPants are the game's final boss fight.

SpongeBob Squarepants in Battle for Bikini Bottom
After fighting their way through many robots, SpongeBob and his friends enter the Chum Bucket and a giant version of SpongeBob, and discovering Plankton was the one who made the robots. Plankton says they were supposed to help him steal the Krabby Patty Formula but instead they're running amuck around Bikini Bottom under nobody's command as Plankton forgot to have the switch on his robot making machine set to "OBEY PLANKTON" as it was set to "DON'T OBEY PLANKTON" Plankton tries to fix it only to realize that the robots are obeying a giant robot version of himself. SpongeBob then goes to battle Robot SpongeBob and Robot Plankton. After he defeats them both, Robot Plankton swears revenge on SpongeBob. However at that moment, More giant robotic versions of Plankton start appearing and they all begin arguing with each other.

Trivia

 * Like the real plankton himself, he is voiced by Mr. Lawrence.