Robot Krabs is a robotic dummy of Mr. Krabs that first appears in the episode "Imitation Krabs." In all its appearances besides that episode, the robot is animatronic. He is mentioned in "Krab Borg."
Robot Krabs is a highly sophisticated robot that has many different features. Inside, from where Plankton controls him, there are hundreds of levers and pulleys to make the robot do many things. The robot is red and constructed from metal, with a metal suit as stated by SpongeBob. He has big eyes and his face acts and looks like a microphone. The robot appears to wear the same clothing as Mr. Krabs, but made from metal.
The robot has a self-destruct device activated by a penny inserted through a coin slot on his belt buckle. He can also disguise himself as a bread toaster.
One of the giveaways that the robot is not Mr. Krabs is that it periodically emits an exhaust fume with an audible noise from an exhaust pipe at the rear whenever it lies.
Role in series
Plankton creates and controls the robot. It is accidentally destroyed at the end of the episode by SpongeBob when he puts a penny into the Self-Destruct Coin Slot, causing the robot and the Chum Bucket itself to be destroyed.
SpongeBob and Squidward mistakenly believe the real Mr. Krabs to be a robot after seeing him exhibit all the features akin to robots in movies. They misleadingly cite him as "Robot Krabs" at one point.
Plankton uses Robot Krabs to steal Krabby Patties. However, this robot is designed more differently. It is rusty, has no shirt or pants design, more crooked arms, uses wheels for legs, and the chest somewhat resembles Mechagodzilla's.