Talk to three teens on the cliff edge near the church on Halloween, and they will give you a quest to find three pentagrams (answer "shipwreck" to their riddle).
The pentagrams can be found:
- On a poster in the secret stage (top of tall building near Snack Falcon, accessible from the rooftop of Gregg/Angus' apartment building).
- Order Doomnuts with Gregg OR speak to the girl at the back of the party with Bea.
- Automatically found in the mines near the end of the game.