In the final batch of episodes for "Supernatural" season 11, Amara hurls a torrent of new evils at Sam and Dean's way. In episode 20, titled "Don't Call Me Shurley," the Darkness, upon her return, brings a killer fog in town with her.

This fog is the same one she unleashed in the premiere of the season, but according to the synopsis for the "Supernatural" episode, it is deemed much more dangerous and stronger to some unknown extent.

It is unclear whether or not it kills a person faster or reaches a greater scope, as suggested by We Got This Covered, but whoever is exposed to it will die for sure, but not until their veins swell and turn black.

This increased potency is suggested by the fact that Dean and Sam's cure, which worked on the original black vein virus, no longer works on this new one. This pushes the duo to race against time to stop the fog from killing more people.

The promo for "Supernatural" season 11, episode 20 teases that Amara has a special message for the brothers. She has Sam and Dean notified by a police officer who died in front of them.

Not long after, Sam points towards the sky, where Amara's message is presumably imprinted. It remains to be seen what the Darkness wants to articulate but it is definitely something sinister.

Apart from Amara's wrath once again demonstrated, this "Supernatural" season 11 episode is made more special due to the return of Chuck played by Rob Benedict. Fans last saw the Lord's prophet in a brief scene in the last season.

Chuck comes back with an "interesting proposal," which may have something to do with defeating Amara. The episode will also reveal what he has been doing after he went off the radar.

Rumor has it that Chuck is actually God aka Amara's brother. Will "Supernatural" season 11, episode 20 finally reveal the truth about this once and for all?

"Supernatural" season 5, episode 20 "Don't Call me Shurley" on May 4 at 9 p.m. ET on The CW.