He looks like original PlanKrab, but with only one green antenna on his eye, dark green body and legs, and with red claws and eyelids. He also has Mr Krabs' black eye pupil. He has Mr. Krabs' voice.
Role in episode
When PlanKrab sees Mr. Krabs and Plankton arguing in the bathroom, he splits into Green and Red PlanKrab and they end up arguing as well. Mr. Krabs and Plankton then tell the two PlanKrabs to shake hands with each other. The handshake melts both PlanKrabs as well as getting rid of PlanKrab for good.
He seems to inhabit more from Mr. Krabs than Plankton.