An Immortal Sorcerer Demanded Overdue Library Books From the Gang to Magically Torture Them

Who was going to destroy Riverdale? Why, that one would be Percival Pickens, an immortal sorcerer who was later revealed to have accidentally entered the Riverdale universe from Rivervale when that bomb went off. Percival did a lot of ludicrous things, but the most ridiculous one was definitely when he brought armed cops to demand the return book to the library from Archie and the gang. Since these books were years overdue, Percival took a meaningful item from each person as collateral, which he then used to cast a spell that mentally tortured them by forcing them to relive their worst traumas. (s6, ep13)