Grimm - Season 1 Episode 21 -

After Juliette stumbles upon a brutal murder, Nick learns the suspected creature, and friend of Monroe, is suffering from a mysterious condition — the inability to completely return to human form. This mysterious condition leads them to a therapist who’s created an artificial drug to suppress the creature side, with horrifying side effects. Meanwhile, the investigation takes a surprising turn when Hank sees something he can’t quite explain.