Monsters vs Aliens: Mutant Pumpkins from Outer Space
One night an unidentified flying object (UFO) appears on Earth and drops a strange green goo into a large pumpkin field. Farmer Jeb, the eccentric owner of the patch, comes outside to investigate but is taken by something off-screen.
Meanwhile, Susan and her monster friends prepare for Halloween celebrations; Missing Link practices scaring, B.O.B. tries to decide what he will be for Halloween and Susan has a "zombie cheerleader" costume ready. Dr. Cockroach however has no interest in Halloween because of a childhood trauma on that same night (which involved a swirly pop). Their prospect of Halloween is cut short when General Monger tells them that aliens have been detected in Modesto and orders them to investigate, on the provision of a need-to-know basis ("It's Halloween, after all. We don't wanna go around scaring folks."). At Farmer Jeb's patch, pumpkins are mysteriously being given away for free, with one family taking the largest one.
That night, Susan and the monsters visit her parents, who have prepared for Halloween eccentrically (with things like "Death by Chocolate Fountain" on display). The monsters investigate the suburbs for aliens while Susan investigates Farmer Jeb's patch. Doc uses his scanner on various people, Link tries to scare people (getting mistaken for Shrek at one point) and B.O.B. has trouble remembering what to say when offered candy by an old lady (even asking her "what is happening right now?") who then gives Doc a swirly pop (believing his appearance to be an intriguing costume), rekindling his interest in Halloween.
At a house belonging to the family that bought the largest pumpkin from the pumpkin patch the pumpkin, named Wicked Jack by the family's son, comes to life and attacks the family. At the pumpkin patch, Susan discovers that all the pumpkins from the patch have also come to life, a result of saturation from the green goo that came from the UFO from earlier. All those in the suburbs come alive also and attack the children, prompting Doc, Link and B.O.B. to protect them. B.O.B., being able to speak "produce" due to his mother being a tomato, attempts to reason with the pumpkins but his attempt fails (the pumpkin B.O.B. talked to apparently said horrible things about his mother, in a salad bar) and Doc discovers that "it's not the children they're after, it's the candy!" and that the more they ate, the bigger the pumpkins would get (literally) "until the whole world becomes their pumpkin patch."
At that moment, Wicked Jack emerges, now a giant pumpkin and assumes leadership of the Mutant Pumpkins. B.O.B.'s bungling leads the pumpkins to the Murphy house. The children and monsters rally against the aliens just as Susan turns up, but Wicked Jack fuses himself with the other pumpkins to become an even bigger giant. The monsters' attempts to defeat Wicked Jack seem to prove futile until Doc realizes from seeing B.O.B. suffering from indigestion (B.O.B. attempted to eat all the candy in the garden to prevent Wicked Jack from doing so) that they must overfeed the pumpkins with candy to bloat them up. He helps by making a Gatling gun platform for that purpose.
All the candy is eventually used up, allowing Wicked Jack to recover. Doc realizes he must give up his swirly pop, which he does, to push Wicked Jack to indigestion. At that point, Susan's parents come outside and are shocked to see the whole thing. Declaring that "no-one ruins a Murphy Halloween", Susan sucker-punches Wicked Jack's head off, allowing him to escape until she whistles for Butteryflyosaurus (dressed as Elvis Presley) to destroy him. All the candy that had been consumed by the pumpkins comes out unscathed, including Doc's swirly pop, which he gives to a young girl. Susan's parents also admit that they will have to get used to sharing her with the whole world.
Unnoticed, a surviving pumpkin tries to sneak away but is found by Link, who scares it into exploding. General Monger arrives to congratulate the monsters as well. But, in a twist ending, some of the pumpkin "blood" (the green goo) saturates a planting of carrots, causing a mutant carrot to be formed.
psychedelic