[Pranks are a family thing apparently. Eli had so much fun with the sock puppet incident that he has decided to keep it going. To extreme levels. Mostly as payback for being wrongly accused.
So, when Henry wakes up in the morning, he'll find a picture of Psychotic Sock Monkey™ holding hostage the stuffed monkey that was in Henry's room, tied up, with Psychotic Sock Monkey™ holding a letter opener threateningly at it along with a note that is terribly scribbled, since, as everyone knows, Psychotic Sock Monkey™ types do not have good penmanship, that says: "This is what happens when people talk. I'll be watching you." sitting by the nightstand of his bed along with the remains of red-tinged cotton that may or may not have been stuffing (but, in actuality, is just a bunch of cotton balls stretched and dyed with red ink).
Yes, Eli is a terrible human being. Yes, he knows he's going to hell. But...he just can't help himself.]