Just about anything can occur on "Supernatural," given its theme and the premise that drives the series. Next Wednesday will mark the first time an imaginary friend visits the show though, given that it was one of Sam's from the past.

Episode 8, titled "Just My Imagination," will air next Wednesday, Dec. 2 on broadcast network the CW at 9 p.m. EST, according to TV Guide.

It shouldn't come as a surprise that everyone has an imaginary friend once in their life. But the things is, most of them have those friends only in childhood. Next week, that won't be the case as Sam Winchester gets a visit from his and he is having a hard time figuring out if he is really there or if he is getting mind tricked by a demon.

According to Spoilers Guide, Sam gets the shock of a lifetime when Sully (guest star Nate Torrence) shows up out of nowhere. He recognizes him instantly, but he does not trust that what he is seeing is really the imaginary Sully or possibly an ominous being invading his head.

Either way, he is there and Sam has to find out why and more importantly how. But the plot thickens when Dean acknowledges Sully's presence. One can almost imagine what kind of surprise that gives Sam considering it was his very own imaginary friend from childhood.

Here's the issue though: Why is he there and what does he want? He wasn't even real to start with, or at least as far as Sam can remember, but he is there in the flesh and he does not seem to be anything evil. So why now?

As it turns out, Sully is real in the imaginary world and now that he has run into his own trouble, he has returned to his previous friend Sam who now hunts down and eradicates evil. So he needs Sam's help with his own problem, which explains a few things but still leaves him a bit dumbfounded to the idea.

Watch the preview below.