Plankton's death robot was one of many inventions created by Plankton. It only appears in the episode "Eek, An Urchin!"
The death robot is a rather small robot that moves around on one wheel. It is light blue and has one red eye, just like its creator, Plankton. It also has a red button near the bottom used for its features, and two robotic antennae on its head representing Plankton's antennae.
Mallet: This is the death robot's main feature. After its target has been chosen, it will start to chase down that target until it smashes it with the mallet.
Super Strength: The death robot uses its arms to rip open anything with ease. This was shown when it tore apart a table and Mr. Krabs' shell.
The death robot is destroyed by Mr. Krabs when it attempts to smash the sea urchin while it is inside his cash register. The death robot rips apart Mr. Krabs' shell, greatly upsetting him. The robot puts him back together but Mr. Krabs then takes the mallet from it and starts to smash it turning it into a lunchbox.
When Mr. Krabs smashes the death robot into a lunchbox, the robot smiles in the picture even though it has no visible mouth.