He is Patrick with a blue cape and some red goggles. When he spins, his clothes will change. Sometimes, a red and black striped suited version of himself, or a form similar to his usual look except with only his underpants worn.
His goal is to defeat the evil Dreaded Patrick from destroying a 2D version of Bikini Bottom in Patrick's Dream. He gets his tasks from a stranger (who sounds like Patrick) which Patrick called "Phone Guy".
Role in Creature from the Krusty Krab
Starfishman To the Rescue
Starfishman first appears after Patrick wakes up from a nightmare. He saw a news broadcast who says that The Evil Dreaded Patrick is attacking Bikini Bottom. Patrick soon jumps out from his Rock and transforms into Starfishman. He proceed to go after Dreaded Patrick, all while doing things such as stopping a train from ramming a citizen, and find pieces of his missing clothes. He also going around the town, searching for detergants. Once he get all of them, Dreaded Patrick appears and reveals his plan: He's going to launch a citizen starfish into space (he states that the starfish's going to be "The First Fish in Space"). He and Starfishman engages in an elevator duel (which is actually Starfishman fighting Dreaded Patrick's minions while avoiding falling objects.) Starfishman wins the duel and goes to rescue the citizen, however, he isn't aware that Dreaded Patrick's minions behind him, who proceed to knock him unconscious. After he wakes up, he realizes that he was tied to the rocket, and blasted into space by his nemesis. However, while he was blasted off into space, he hits an ring shaped asteroid, which falls into earth and traps Dreaded Patrick in it.
Continuing from the Starfishman To the Rescue, Patrick wakes up, still tied to the rocket. After realizing what happened, he flies the rocket through space, while trying to break free from the rope. Throughout his flight, he keep getting attacked by a Krabby Patty-shaped UFO. He flies through a black hole (filled with gigantic objects like doors and a shovel) and finds a space station on a collision course with asteroids. While inside, he succeeds in untying himself from the rocket, and proceeds to man a laser turret to destroy the asteroids, meanwhile avoiding other objects (Such as satellites and rockets). After destroying the incoming asteroids, he leaves the station on the rocket again, also being able to use the rocket's laser guns. Starfishman pursues the Krabby Patty UFO, and in a following dogfight, takes down the UFO. He then flies back towards Earth, but cannot stop the rocket from heading down.
Continuing from Rocket Rodeo, Patrick again wakes up on the rocket, which has plunged into the ocean and is heading straight down towards the rooftops of Bikini Bottom. He then panics and presses a button on the side of the rocket, which stops it, and he gets off. After landing, he finds Mermaid Man on the rooftops and begs him to help him defeat a now-enormous Plankton. After a series of battles with Giant Plankton and his minions (which involves doing things such as smashing his fingers or calling in the Bikini Bottom Defense Force), Mermaid Man shows Patrick four hidden shrink lasers, which Patrick uses on Plankton to make him small again. A shrunk Plankton falls on top of Patrick, thus ending the battle.
In the final level of the game, Hypnotic Highway, Starfishman is an unlockable racer. If the player manages to get him, he flies the same rocket that he flew in Rocket Rodeo around Hypnotic Highway, against SpongeBob's kart and Plankton's hovercraft.
He is similar to Patrick-Man, as they are both superhero alter-egos.