The Winchester brothers will deal with another strange case in the next episode of "Supernatural" season 11.

In episode 19, titled "The Chitters," Sam (Jared Padalecki) and Dean (Jensen Ackles) will look into the mysterious disappearances that happen every 27 years in a small, sleepy town in Colorado. The local police told them that aliens allegedly attack the town's residents. However, the two learned later on that the culprits are called The Chitters. They are described as human-like creatures who possess bright, green eyes.

As they arrive in town, the Winchester brothers will meet two hunters who also aim to find the perpetrators. But the hunters are doing it for their personal vendetta.

The episode is slated to air on Wednesday, April 27.

Meanwhile, The CW released the first look of Chuck's (Rob Benedict) return in the 20^th episode of "Supernatural" season 11.

The synopsis for the episode, titled "Don't Call Me Shurley," revealed that Chuck will return to present an interesting proposal to the Winchester brothers. However, the synopsis does not mention Chuck's real intentions.

The official synopsis for episode 20 reads:

"Amara (guest star Emily Swallows) unleashes a dark fog on a small town, causing everyone to go mad. Dean and Sam realize this is a stronger version of the original black vein virus Amara previously unleashed. They team up with the sheriff to protect the town but their old remedy no longer works. Meanwhile, Chuck returns with an interesting proposal."

Chuck, the author of the "Supernatural" book series using the pseudonym Carver Edlund, was last seen in season 10 episode 5, titled "Fan Fiction." He writes about the adventures of the Winchesters and turn them into novels. But speculations claim that Chuck is actually God himself. Will the episode, airing May 4, finally reveal Chuck's real identity?