A wererat is a fictional creature akin to a werewolf, but shapeshifting into the form of a rat instead of a wolf. This type of therianthrope is rare in historical legends, but has become common in modern role playing games and fantasy fiction inspired by them. They are commonly portrayed as sewer-dwelling scavengers and opportunistic thieves.
There are some references to "goblin rats" or rat-themed yōkai in some Japanese myths that may or may not be the source for the wererats in games and novels. Brad Steiger has written about wererat sightings in Oregon, mostly by children. Some of the Benandanti were supposed to change into mice.
In the Dungeons & Dragons fantasy role-playing game, the wererat is one of several different types of animalistic forms. Not lycanthropes, for the word reflects a lupine, or wolven, form, but other transformations of the "were" species. They are also found in various games inspired by or based on Dungeons & Dragons such as NetHack and Neverwinter Nights.
In the American Manga Gold Digger wererats were one of several lycanthropic races created by an enchanter named Iceron. Five characters important to several recent events are wererats. Sherissa, the near immortal leader of the wererat clans, Gothwrain her thrall, servant and apparent enemy, and also three young warriors/assassins collectively known by fans as the Mall Rats (Gold Digger): Lydia McKraken, Romeo Ellis and Moisha Rich.
- Johnson, Kristin (September 1998). "Ecology of the Wererat". Dragon (TSR) (251).
- Cook, David, et al. Monstrous Compendium Volume One (TSR, 1989).
- Hall, J. (2003). Half Human, Half Animal: Tales of Werewolves & Related Creatures. Bloomington, IN: Authorhouse. ISBN 1-4107-5809-5.