Robot Plankton is the main antagonist of the console versions of the 2003 SpongeBob SquarePants video game SpongeBob SquarePants: Battle for Bikini Bottom and its 2020 remake SpongeBob SquarePants: Battle for Bikini Bottom - Rehydrated. He is a giant robotic version of Plankton (from Plankton's perspective; as he is the same size as SpongeBob when compared to him). He and SpongeBot SteelPants are the game's final boss.
He was voiced by Doug Laurence like his organic counterpart, although Robot Plankton speaks in a more robotic tone.
After fighting their way through many robots, SpongeBob and his friends enter the Chum Bucket and find a giant version of SpongeBob, and discover Plankton was the one who made the robots.
Plankton says they were supposed to help him steal the Krabby Patty Formula, but instead they ran amok 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 the problem only to realize that all the robots are instead obeying a giant robotic version of himself. SpongeBob then goes to battle SpongeBot SteelPants and Robot Plankton.
When SpongeBot SteelPants is defeated the first time, Robot Plankton rants about it and fixes the SpongeBot by giving it anchor arms to strengthen it. He then flies into SpongeBot's ear and SpongeBob has to fight him in SpongeBot's brain. After he defeats them both, Robot Plankton swears revenge on SpongeBob.
However, at that moment, the Duplicatotron 3000 malfunctioned and rapidly created more giant robotic versions of Plankton, where they all begin arguing with each other about destroying each other. They are likely destroyed afterward.
- Somehow, Robot Plankton did not make an appearance in the Game Boy Advance version of BFBB, despite SpongeBot appearing in that game. Neither appeared in the PC version either. So it is likely that SpongeBot is the main antagonist of the GBA version while Plankton is the main antagonist of the PC version.
- Robot Plankton addressed SpongeBot with feminine pronouns and apparently was in a relationship with "her" saying they were going to be married the following week.
- In Rehydrated, Robot Plankton is one of the playable characters in the multiplayer horde mode.