There's a group of trolls, but one of them runs away into the sewers. He then hides in the trash, puts on some clothes that were in the bin, and runs off mimicking some nearby dancers.
The next day, the trolls arrive on the Queensborough Bridge. The Ghostbusters wake up (with Peter angry that Slimer slept on him and got slime in the bed) and get a call about the trolls. Egon and Ray recognise that the creatures are trolls, but Winston and Peter initially don't believe them and Peter calls Ray a kid for comparing the situation to Three Billy Goats Gruff.
Egon explains that trolls are mean creatures who dislike humans and hang out under bridges, and warns the other Ghostbusters that zapping them could either turn them to stone or make them larger and more malevolent. It's then revealed that he knows the trolls' language, so he translates the leader of the trolls, who wants the runaway one back in twelve hours or he'll destroy the city with "fireflies" (flying creatures that are constantly burning).
Peter and Egon search the Holland Tunnel, while Ray and Winston search Times Square, but to no avail. They eventually find the missing troll in a nightclub, but by then, twelve hours have already elapsed and the troll leader sends down the fireflies. They're immune to proton streams, but vulnerable to water, so the Ghostbusters drench them with a water tower and save the city. Then, they apparently turn the runaway troll to stone, but it then turns out they'd paid the owner of a lawn decoration store to make a statue of a troll to trick the others. The Ghostbusters then send the runaway troll to Chicago, where Peter's friend is.
This episode provides examples of
- All Trolls Are Different: Trolls in this series are short, ugly creatures that are usually antagonistic and hate humans, and they have their own language.
- Arbitrary Skepticism: Despite having dealt with the paranormal on a day-to-day basis, Peter and Winston initially don't believe in trolls.
- Attack of the 50-Foot Whatever: Discussed when Egon reveals that zapping a troll with a proton pack may make it larger.
- Cyclops: One of the trolls has one eye.
- Ectoplasm: Slimer sleeps on Peter's bed and gets gunge all over the blanket.
- Evil Laugh: When the trolls first arrive on the bridge, they laugh maniacally.
- Facepalm:
- Peter facepalms when he sees slime on his bedclothes.
- He then does it again when he's bemused at Egon and Ray's talk of trolls.
- Fantastic Racism: The trolls are said to hate humans.
- From Bad to Worse: Ray says that the time they have before the firefly attack is almost up... then Egon corrects him that it is up.
- Happy Dance: The runaway troll dances with joy when the Ghostbusters trick the other trolls into thinking he was turned to stone.
- I Don't Think That's Such a Good Idea: Ray wants to blast the trolls, but Egon warns him not to lest they grow and become meaner.
- Let's Split Up, Gang!: Peter and Egon search the tunnels, while Ray and Winston search Times Square.
- Logical Weakness: The fireflies, being made of fire, die if they get wet.
- My Species Doth Protest Too Much: The runaway troll is much friendlier to humans than the rest of the trolls.
- Not Always Evil: The book Egon reads describes all trolls as "vicious" and "mean", and while most of them indeed are, there does turn out to be one relatively friendly troll.
- Pun-Based Creature: A rare example of one Played for Horror — the fireflies are literally made of fire.
- Speak in Unison:
- When Egon determines the creatures are trolls, Peter and Winston say, "Trolls!?" in unison.
- When the guys appear to deal with the trolls, a group of civilians chants, "Ghostbusters!" in unison.
- Suddenly Fluent in Gibberish: Egon is suddenly revealed to be able to understand trolls.
- Taken for Granite: Discussed and later subverted. Egon reveals that being zapped with a proton stream may turn a troll to stone, and then later it appears this happened to the runaway troll, but it was all a trick.
- Tempting Fate: Ray asks what could be so bad about fireflies, but then they turn out to be literally made of fire.
- The Unintelligible: The trolls speak in a strange, babbling language.
