Sympathy for the Devil

"So let me get this straight. You're an immortal creature that takes over people's bodies and your most recent host is my detective partner." "Yeah, that's pretty much it." It wakes up in The Corridor, chooses a life, lives the life, dies, and ends up back in The Corridor. Again and again and again. Then, It wakes up in Scorpius Malfoy's body and faces a challenge.