This story is a late-occuring event from My Roommate is a Monster…Tamer, released early for Halloween.

As a Monster Tamer, Vinyl normally only deals with invisible Monsters and Equestrian mythical wildlife. However, when something escapes Tartarus, Vinyl is recruited personally to catch it.

(The main story is a crossover with Monster Allergy, though this chapter in particular borrows from Reaper as well.)