The Electric Eye is a character who appears in the episode "Bottle Burglars."
It is basically a big eye that resembles Plankton's. It has a greenish sclera, a red pupil, and a black iris. It is also held by a metal bracket.
Role in episode
Squidward and SpongeBob, while looking for the Krabby Patty secret formula, encounter this machine. It states that it will do a retina scan on them. SpongeBob uses a mugshot of Plankton to gain access.