As the title indicates, "Metamorphosis" draws from Kafka's short story of the same name, most of all Will's transformation. Instead of an insect, though, he becomes part lizard, part plant. The plot follows Will as he first finds pleasure in climbing up the walls, before realizing the horrible situation he's in and the abnormal physiology takes over.
While everything returns to normal at the end of the episode, Ranna covertly sends a message to the Sanctuary, indicating that she cares somewhat about them and that she doesn't have enough power to do things in the open.
Score: 8.5/10