|This article contains canon information corresponding to the Tales of Arcadia franchise. That means all information in this article is true and has appeared/been validated officialy on-screen.|
Armed with an ancient troll-hunting tool, Jim and Toby set out to unmask the Changelings living among them. Claire makes Jim a tempting offer.
After Jim finds the Killahead Bridge has been moved, he must use a gaggletack (a horseshoe-shaped artifact that reveals the true nature of a changeling by physical contact) to find who in Arcadia is a changeling. If he touches a changeling with the gaggletack, they change from human form to troll form, so Jim and Toby go around the school touching everyone with the gaggletack to see who is a changeling.
- Kelsey Grammer as Blinky
- Anton Yelchin as Jim Lake Jr.
- Charlie Saxton as Toby Domzalski
- Lexi Medrano as Claire Nuñez
- Ron Perlman as Bular
- Jonathan Hyde as Mr. Strickler
- Fred Tatasciore as AAARRRGGHH!!!
- Brook Chalmers and Tom Kenny as Rot and Gut
- Guillermo Del Toro as Dr. Muelas
- Laraine Newman as Miss Janeth
- Melanie Paxson as Gladys
- Cole Sand as Eli Pepperjack
- Matthew Waterson as Draal
- Victor Raider-Wexler as Vendel
- Thomas F. Wilson as Coach Lawrence
- Steven Yeun as Steve Palchuk
- The song that is heard in the scene of Dr. Muelas while singing is "Cielito Lindo".