When Jim and Toby investigate a Goblin attack, they discover Changelings are secretly living amongst them and rebuilding the Killahead Bridge!
Tropes for this episode include:
- Battle Theme Music: In the Hall of the Mountain King plays during Jim's fight against Nomura.
- Changeling Tale: The premier episode to changelings and goblins.
- Dodgeball Is Hell: During gym. Playing against Steve, Jim accidentally hits Claire in the face as she walks in.
- Expy: The goblins present in the show are very Gremlin-esque.
- Facial Markings: Their leader is often seen drawing a mustache on their faces with a marker. Should the leader die, the next in line will draw an identical one on themselves.
- Getting Crap Past the Radar: Toby manages to get Steve away from Claire by telling him that the neanderthals at the neanderthal exhibit were topless.
- Honor Before Reason: Even if it was a complete accident, even if they have other things they need to do of higher priority, even if you didn't actually do it, if goblins see a dead one of their own, your best option is to run. Very fast.
- Misplaced Retribution: Goblins aren't bright enough to link cause and effect; when one of them is killed by a truck, they take their vengeance out on the truck instead of on the driver. Jim uses this knowledge to his advantage and defeats Nomura by tripping her such that she lands on and kills a Goblin.
- Murder by Mistake: Every goblin death was done by accident (though Jim intended the second death to get the goblins to attack Nomura).
- Reality Ensues: Jim and Toby get arrested for breaking into the Museum.
- The Reveal: Jim and Toby learn that Changelings exist, that the Killahead Bridge is being reassembled.
- Skewed Priorities: Toby's more interested in his Chubby Tracker going missing and getting points for swag than the goblin situation.
- Staff of Authority: The magic marker, used to draw on the mustache, denotes leader of the Goblin gang. When a leader is killed, the first goblin to grab the marker and draw on the mustache is the new leader.
- Stern Teacher: Blinky lets Jim and Toby off for the night when Jim rants about the convoluted nature of Trollhunter rules and the stress of multiple responsibilities all at once. He's not thrilled with the idea of the Chompsky living in Toby's house though.