The Two-Headed Monster is a unnamed member of Ludo's Army and a minor antagonist in the cartoon series Star vs. the Forces of Evil.
They first appeared in "Star Comes to Earth" as one of the many monsters Ludo brings with him to Earth in order to get Star's wand. They fight Marco but Marco karate chops both of their heads. They are soon defeated by Star's narwhal blast.
They later appear in "Match Maker" to once again get the wand. Star and Marco fight them and latter they get his with Star's dagger hearts. Then get defeated by Star's turbo nuclear butterfly blast and retreat with the others.
In "Cheer up Star", Star gets depressed when Oskar doesn't call her. Marco tries to cheer her up by using her wand to lure Ludo and his army to Earth for Star to fight. They are seen sweeping bones, when they notice the wand and follow it along with several other monsters. Star soon fights them and defeats them along with the other members of Ludo's army with her maple syrup spell.
In "Brittney's Party", the Two-Headed monster appears with Ludo and the rest of his army. They hijack the party bus and plan to drive it into a dimensional portal with people still inside it. Star fights them on the roof, while fighting she blasts the Two-Headed monster and they fall, grab on to a streamer, slam into a window, and scare a few passengers. They later fall off and land into an Asian man's car.
In the beginning of "Lobster Claws" the Two-Headed monster is seen fighting Star and Marco with the other monsters in Ludo's army. Soon they are pelted with fiery cupcakes and loses the wand because of the dimwitted action performed by Lobster Claws. They return to Earth once again to get the wand and another fight begins. Once Lobster Claws gets the wand he becomes corrupted by it's power that was amazing to Ludo's army. They soon welcome him back to the team.
In the beginning of "Fortune Cookies" the Two-Headed monster fights Star and Marco with the rest of Ludo's army. They are soon defeated afterwards, later in the break room of Ludo's castle they are having a dance off with the Frill-neck Monster. When Toffee devises a trap for Star and Marco, Two-Headed monster and Frill-neck monster are disguised as break dances to distract Star. When the monsters start to attack and Star gives the Two-Headed monster a hug which makes them happy because they haven't been hugged since middle school. This cause them to reveal the plan to Star and she defeats them all with a mushroom blast.
In "Mewnipendence Day", after Buff Frog loses his espionage to Toffee he fears he might loses his job as second-in-command to one of the other monsters like the Two-Headed monster.
In "Marco Grows a Beard", he comes to Earth with the rest of Ludo's army to get the wand. After they fail Ludo immediately blames the monsters and takes away their milkshake privileges. However, Toffee convinces the monsters to turn on Ludo and throw him out of the castle.
Their last appearance was in "Storm the Castle" as one of the many monsters working for Toffee now. When Star uses the whispering spell to destroy her wand Two-Headed monster is caught in the explosion. It is unknown if they died or survived in the explosion.
In "Starfari", it is revealed that the Two-Headed monster survived the explosion and is living in a monster village.
In "Is Another Mystery", Two-Headed monster leaves Mewni along with their fellow monsters.
Toffee | Ludo | Meteora Butterfly | Mina Loveberry | Tom Lucitor | Gemini | Rasticore | Seth | Giant Spider | Bald Eagle | Buff Frog | Bearicorn | Beard Deer | Three-eyed Potato Baby | Big Chicken | Two-Headed Monster | Giraffe Monster | Boo Fly | Lobster Claws | Warthog Monster | Crocodile Monster | Frill-neck Monster | Lizard Monster