He is a green metal fish in a purple metal suit. He wears a black top hat with a white stripe around the bottom. Before he enters the Krusty Krab, he puts on a fake mustache.
He enters the Krusty Krab to tell SpongeBob that he will win a million-dollar bill if he reveals the Krabby Patty secret formula. After SpongeBob says that discussing the formula is forbidden, Plankton angrily bursts out of the disguise's teeth to threaten SpongeBob, getting caught by Mr. Krabs in the process.
Creature from the Krusty Krab
The head of this robot is later seen in the console version during the minigame of the Supersized Patty level.