To help Ludo obtain the wand (Formerly).
Three-eyed Potato Baby is a member of Ludo's Army in Star vs. the Forces of Evil.
Three-eyed Potato Baby first appears in "Star Comes to Earth" as one of the many monsters Ludo brings to Earth to help him get Star's wand. He along with Big Chicken fight Star and Marco together but both of them get beaten and blasted with a narwhal blast. He then retreats into a dimensional portal with the others.
In "Match Maker" Three-eyed Potato Baby appears with the rest of Ludo's army. He fights Star and Marco while in the process gets hit in the face with a rake and kick in the gut by Marco. He is soon blasted with a turbo nuclear butterfly blast and retreats.
In "Cheer up Star" Three-eyed Potato Baby is one of the monsters Marco leads to Earth in an effort to cheer up Star. But is soon defeated afterwards.
In "Brittney's Party" once Ludo and his army hijack the party bus he orders Three-eyed Potato Baby to take the wheel. He picks up the bus driver, throws him out of his seat, puts on his hat, and beings to drive it towards a dimensional portal. Marco knocks him out and is seen leaving the bus in pain and agony like all the rest of the monsters.
At the beginning of "Lobster Claws" He fights Star and Marco in the backyard. Thanks to Lobster Claws' dumb mistake he and the other monsters get pelted with fiery cupcakes and retreats. He later returns to once again get the wand, while fighting he gets thrown into the house. When Lobsters Claws get the wand he loses control impressing Three-eyed Potato Baby and the other members of Ludo's army. Then gets blasted with a daisy explosion and retreats.
At the beginning of "Fortune Cookies" He fights Marco and Star in their backyard and get defeated again. Back at the castle he is in the break room getting water with Boo Fly in the jug. When Ludo tries to find new henchmen Three-eyed Potato Baby (or someone who looks like him) is applying for the job. But Ludo terns him down because he makes absolutely no sense. He then fights Star and Marco in valley thanks to a trap set up by Toffee. But gets blasted with a mushroom blast.
In "Mewnipendance Day" after Buff Frog loses his espionage to Toffee he fears of losing his job to one of the other monsters like Three-eyed Potato Baby.
In "Marco Grows a Beard" Three-eyed Potato Baby comes to the Diaz household with all the other monsters to find the wand in Marco's hair. At the end Ludo blames the monsters for losing the wand and takes away their milkshake privileges. But, Toffee manages to get the monsters on his side to turn on Ludo and throw him out of the castle.
His last appearance was in "Storm the Castle" as one of the monsters serving Toffee now. When Star destroys her wand Three-eyed Potato Baby is caught in the explosion. It is unknown if he died or survived.
In "Starfari" it is revealed that Three-eyed Potato Baby survived the explosion and is living in a monster village.
In "Is Another Mystery" Three-eyed Potato Baby leaves Mewni along with his fellow monsters.