Marty is married to Janet and comes to Patrick's house for Annual Starfish Day. He is Patrick's fake father. Like Janet, who resembles Marge Simpson, Marty resembles Homer Simpson. He has bushy eyebrows and wears a gray tank top, with blue shorts. He is a darker shade of pink than most other starfish in the series.
He only appears in "I'm With Stupid," where SpongeBob pretends to be dumb for Patrick's fake parents. He is not quite smart himself though.
Even though SpongeBob reveals the truth about Patrick, Marty and Janet still don't believe Patrick is dumb (being dumb, themselves) and start laughing at SpongeBob, who runs out of the house in fury. When Janet and Marty reveal their real names, Patrick gasps and demands to know who they are.
Before Patrick can do anything, Squidward arrives with another starfish couple, who reveal themselves to be Patrick's real parents. Janet and Marty realize they don't have a son and leave.