He is a light green fish who wears a dark blue ski mask.
Role in series
He is seen in SpongeBob's imagination. At the Krusty Krab, when SpongeBob loses his name tag he becomes scared and wonders who has his it. He then thinks of the identity thief, robbing a bank, wearing SpongeBob's name tag, and shouting "Attica!" This thought immediately frightens him.
"The Krabby Kronicle"
The identity thief is seen robbing a bank while SpongeBob is trying to find some interesting events to put in the newspaper.