He is a tall fish with thin arms and a wavy dorsal fin. He wears a black and white striped prisoner's uniform with a cap. In his first appearance, he is light blue with bright green arms and a matching green dorsal fin. In his second appearance, he is orange with a forest green dorsal fin.
The light blue cellmate is first seen eating Plankton's food. Not knowing, he eats Plankton, and as Plankton calls out his own name from inside, the purple cellmate gets angry at the light blue cellmate and the latter gets beaten up by him and Reggie.
After Plankton gets everyone settled down, the light blue cellmate agrees to help Plankton escape prison and take the Krabby Patty secret formula with the use of chum. However, the light blue cellmate and the others are all soon arrested and taken back to prison.