"Monster Arm" is the first segment of the third episode of Star vs. the Forces of Evil. It premiered on April 6, 2015 alongside "The Other Exchange Student".

On February 23, 2015, the episode was released early on, the WATCH Disney XD app, and Disney XD on Demand.


Star Butterfly watches Marco practice Karate and monologue how he's going to defeat Jeremy Birnbaum, when he breaks his hand on a plank of wood. Star, feeling sorry for her friend tries to repair it with her wand, but instead causes the entirety of Marco's arm to turn into a giant tentacle.

Later at school, Lars is picking on one of the unpopular students, when Marco accidentally uses his arm to hit Lars several times, which sends the bully off, crying. The students welcome Marco as a Hero. Star spends two nights trying to find a reverse tentacle spell for Marco, but can't seem to find the right spell for it. The next day, Star finally finds the correct spell, and finds Marco working out with the tentacle arm, which makes Marco arrogant. Star calls the arm a bad influence, and Marco pushes her out of the room. The Tentacle begins talking to Marco, and subtly reveals his evil plans, while a fooled Marco agrees to keep using the tentacle for the tournament.

When the day of the tournament arrives, Star sits next to Marco's friends, and they acknowledge that she is looking terrible, which she explains is due to her trying to find a cure for the tentacle. As the tournament starts, Jeremy is revealed to be a small kid, and Marco begins brutally fighting him, using the tentacle arm. The tentacle becomes sentient again, and begins to coerce Marco into finishing Jeremy. Marco, knowing the Tentacle is evil, calls Star for help. Star uses the want to try and return the arm to normal, but it makes other objects around the room turn into hands. Eventually, the Tentacle gets caught by all the various hands, and Star turns Marco's arm back to normal, but not before the Tentacle promises to return. As Marco's arm is still broken, Jeremy proclaims he wins, before accidentally dropping his Brass Knuckles, which he used to win. The Sensei claims neither has won, due to them both bringing shame to the sport. Marco apologizes to Star, and stresses his concern about the arm returning, and an unsure Star tells Marco he shouldn't worry.



The Disney Wiki has a collection of images and media related to Monster Arm.


  • This is the first episode that shows Star wearing her hair differently.


  • When Star finally gets the spell right, the hand had five fingers, while the characters in the show normally have four.
  • In the scene where Marco is fighting the monster arm, Star seems to be aware of the situation, even though at this point she should have fallen asleep.

International Premieres

v - e - d
StarVTFOE Logo
Star vs. the Forces of EvilStar and Marco's Guide to Mastering Every DimensionComic Books
Star ButterflyMarco DiazPony HeadLudoRiver ButterflyMoon ButterflyGlossaryckFerguson O'durgusonAlfonzo DolittleJackie-Lynn ThomasJanna OrdoniaBrittney WongMr. and Mrs. DiazOskar GreasonMiss SkullnickTom LucitorLaser PuppiesJeremy BirnbaumBuff FrogBuff Frog's TadpolesMonster ArmPrincipal SkeevesPixie EmpressPrincess SmooshyToffeeMeteora ButterflyMina LoveberryEclipsa ButterflyHekapooOmnitraxus PrimeRhombulusLekmetKellyLove SentenceMariposa Diaz
Season One: "Star Comes to Earth/Party With a Pony" • "Match Maker/School Spirit" • "Monster Arm/The Other Exchange Student" • "Cheer Up Star/Quest Buy" • "Diaz Family Vacation/Brittney's Party" • "Mewberty/Pixtopia" • "Lobster Claws/Sleep Spells" • "Blood Moon Ball/Fortune Cookies" • "Freeze Day/Royal Pain" • "St. Olga's Reform School for Wayward Princesses" • "Mewnipendance Day/The Banagic Incident" • "Interdimensional Field Trip/Marco Grows a Beard" • "Storm the Castle"

Season Two: "My New Wand!/Ludo in the Wild" • "Mr. Candle Cares/Red Belt" • "Star on Wheels/Fetch" • "Star vs. Echo Creek/Wand to Wand" • "Starstruck/Camping Trip" • "Starsitting/On the Job" • "Goblin Dogs/By the Book" • "Game of Flags/Girls' Day Out" • "Sleepover/Gift of the Card" • "Friendenemies/Is Mystery" • "Hungry Larry/Spider With a Top Hat" • "Into the Wand/Pizza Thing" • "Page Turner/Naysaya" • "Bon Bon the Birthday Clown" • "Raid the Cave/Trickstar" • "Baby/Running with Scissors" • "Mathmagic/The Bounce Lounge" • "Crystal Clear/The Hard Way" • "Heinous/All Belts are Off" • "Collateral Damage/Just Friends" • "Face the Music" • "Starcrushed"
Season Three: "The Battle for Mewni" • "Scent of a Hoodie/Rest in Pudding" • "Club Snubbed/Stranger Danger" • "Demoncism/Sophomore Slump" • "Lint Catcher/Trial by Squire" • "Princess Turdina/Starfari" • "Sweet Dreams/Lava Lake Beach" • "Death Peck/Ponymonium" • "Night Life/Deep Dive" • "Monster Bash" • "Stump Day/Holiday Spellcial" • "The Bogbeast of Boggabah/Total Eclipsa the Moon" • "Butterfly Trap/Ludo, Where Art Thou?" • "Is Another Mystery/Marco Jr." • "Skooled!/Booth Buddies" • "Bam Ui Pati!/Tough Love" • "Divide" • "Conquer"
Season Four: "Butterfly Follies" • "Escape from the Pie Folk" • "Moon Remembers/Swim Suit" • "Ransomgram/Lake House Fever" • "Yada Yada Berries/Down by the River" • "The Ponyhead Show!/Surviving the Spiderbites" • "Out of Business/Kelly's World" • "Curse of the Blood Moon" • "Princess Quasar Caterpillar and the Magic Bell/Ghost of Butterfly Castle" • "Cornball!/Meteora's Lesson" • "The Knight Shift/Queen-Napped" • "Junkin' Janna/A Spell with No Name" • "A Boy and His DC-700XE/The Monster and the Queen" • "Cornonation" • "Doop-Doop/Britta's Tacos" • "Beach Day/Gone Baby Gone" • "Sad Teen Hotline/Jannanigans" • "Mama Star/Ready, Aim, Fire" • "The Right Way/Here to Help" • "Pizza Party/The Tavern at the End of the Multiverse" • "Cleaved"

Royal Magic WandDimensional ScissorsMagic Instruction BookStar's Notebook of Spells
I'm from Another Dimension Closing ThemeShining StarSpace UnicornAwesome FeelingToo Little Too LateWaiting for MeJust FriendsThe Ballad of Star Butterfly
MewniEcho CreekEcho Creek AcademySt. Olga's Reform School for Wayward PrincessesDiaz House
See Also
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