Bisclavret is a 12th century Anglo-Norman lai by Marie de France.
For unknown reasons, Bisclavret must transform into a wolf every week. His wife steals his clothing, without which he can't change back. One day, the king his friend goes hunting in the woods. Bisclavret jumps at him and paws his foot like a petitioner, and the king, impressed, grants the wolf his life. Bisclavret goes with the hunting party and stays at court. Everyone is so impressed by his nobility and gentleness that when his wife and her new husband appear at court, and he attacks them, the king concludes that they must have wronged the wolf and imprisons them until they confess. With his clothing back, Bisclavret can return to human form.
- Involuntary Shapeshifter: Bisclavret
- Lamarck Was Right: Bisclavret tears off her nose in the attack. Her children are born without noses.
- Make the Dog Testify: If the wolf, which has been consistently kind and well-behaved for years, suddenly attacks someone without warning, it must have some reason to attack them.
- Nameless Narrative: Played With; the protagonist is originally just called "the baron," but once he reveals that he's a werewolf the narration starts calling him "Bisclavret," which means "werewolf," as though it was his name. Everyone else is just called by their title.
- Noble Wolf: Bisclavret is this in his wolf form.
- OOC Is Serious Business: An inexplicably tame wolf suddenly acts violently toward two specific people, who are eventually revealed to be the ones who got him trapped in animal form.
- Our Werewolves Are Different: They're in their right mind even in wolf form. Or at least Bisclavret himself is; the opening of the tale suggests he may be atypical. Also, his clothes seem to be the Transformation Trinket, as he must remove them to transform and regain them to turn back.
- Reasonable Authority Figure: The king.
- Shapeshifter Mode Lock: Bisclavret cannot resume human form unless he gets his clothes.
- Shapeshifting Excludes Clothing: An unusual version: as far as we know, Bisclavret literally has to take off his clothes to transform, and then can only change back if he puts them back on.
- Standard Royal Court: The king's.
- Transformation Trinket: There's nothing to indicate that the baron's clothes are magical by themselves, but he has to remove/regain them in order to change form.