Things are going to get extremely weird for Sam in next week's episode of "Supernatural." Very aptly titled "Just My Imagination," the younger Winchester will be reunited with someone from his past – his childhood imaginary friend, Sully.

In the promo for the upcoming, sure-to-be-fun episode of the hit CW series, Sully pops out of nowhere, startles Sam and in turn, gets a punch in the face. As the hunter looks in horror at his imaginary friend that seems to have materialized, Sam mumbles "This is not happening."

Dean, as fans would have imagined, isn't at all loving Sully's reappearance. "The whole imaginary thing was dumb then and it's dumb now," he complains to Sam in the "Supernatural" season 11 sneak peek. However, it looks like Sully has an important reason for coming back.

Although it seems that at first Sam is the only one who can see his imaginary friend, Sully will eventually become visible to Dean him too. It remains a mystery how or why this is possible but as the older Winchester declares, the place has officially become "Crazytown."

The synopsis for the upcoming "Supernatural" season 11 episode teases that the episode will be flashback-heavy as it will give fans a look at Sam and Sully's friendship when he was still a youngster. This will also reveal why after all these years, Sully showed up once again.

As Dean and Sam figure out how Sully came back to life, the brothers will also deal with a murderer with a "wild imagination." As the duo checks out the crime scenes, Sully will be there with them. It looks like he could be of great help to them too.

Media outlets expect this episode to be fun, exciting and unforgettable. It should be an awesome filler for fans as they wait to know more about Darkness.

"Supernatural" season 11 episode 8 "Just My Imagination" will air Dec. 2 at 9 p.m. ET on The CW.