Supernatural season 11 returns with an all new episode where fans will get a glimpse of Sam's past as his imaginary friend Sully appears again. Episode 8 titled Just My Imagination will air this Wednesday at 9.02pm EST on The CW.

Warning: Spoilers Ahead

According to the official synopsis: "Sam (Jared Padalecki) is shocked when his childhood imaginary friend Sully (guest star Nate Torrence) makes an unexpected appearance. Sam can't understand why he'd see Sully now but what's even more surprising is that Dean (Jensen Ackles) can see him, too. Flashbacks reveal young Sam's friendship with Sully and why he needed him."

Click here to watch the episode online on the official CW website (only in the US).

A new promo shows Sam entering his room and finding a lot of candies. He looks around confused as his childhood imaginary friend Sully appears and says: "Surprise." Sam punches him on the face and utters: "This isn't happening."

Sam then explains to Dean that he can see his imaginary friend as Dean maintains: "This whole imaginary friend thing is dumb then and dumb now." The brothers will find out that someone is killing children's imaginary friends and they investigate and get to the bottom of it.

The network has also revealed the synopsis for the fall finale episode titled O Brother, Where Art Thou? The chapter will finally reveal Amara's revenge plot, before the show goes on a winter hiatus. In the previous episode, we learned that Darkness, aka Amara, is God's sister and that God had to lock her away to create mankind.

The official synopsis reads as follows:

Amara (guest star Emily Swallow) unleashes her power on the local townspeople as she issues a shocking challenge. Dean (Jensen Ackles) tries to better understand the hold Amara has on him, while Sam (Jared Padalecki) and Crowley (Mark Sheppard) come up with a plan that could have disastrous consequences. Robert Singer directed the episode written by Eugenie Ross-Leming & Brad Buckner.

The fall finale episode will air on 9 December on The CW.