Chumbot
The Chumbot only appears in the episode Enemy In-Law. Plankton uses it to bring the people to his restaurant, but left angrily when Plankton captures them to be demanded to eat here. When Plankton sees Betsy Krabs, he falls in love with her. The Robot is so tough that its fist can break a huge rock in small pieces. The Robot is seen again at the end of the episode.
Looks
He is silver, and has antennas (like Plankton). He is practically like Plankton, but a robot and is bigger. (Betsy thought Plankton was the robot.)