WARNING: The following article contains spoilers for the Season 15 premiere of Supernatural, which aired Thursday on The CW.
At the climax of Supernatural's 14th season, Jack Kline's life was snuffed out -- Thanos-style -- by the snap of God's fingers. However, he wasn't the only victim of Chuck's nigh-unparalleled powers that night. Sam Winchester was also injured during the stand-off with the Lord. And in the Season 15 premiere, we get to see part of the damage, as well as the reverberations it could have throughout the rest of the show's final season.
Being a Nephilim, Jack's archangel and human makeup made him virtually impossible to kill. So much so that Chuck has to conjure up a special weapon to get the job done: The Equalizer. The gun's formal name, The Hammurabi, comes from a Babylonian ruler famous for inventing his own code of law in Mesopotamia -- a fitting reference for a writer like Chuck whose own cosmic rules created the illusion of free will for humanity in Supernatural's universe.
Just as The Colt was said to kill anything, Chuck claims the same of The Equalizer. But as Sam soon finds out when he puts this claim to the test -- by firing on God -- this isn't strictly true. (Writers always lie, Castiel rationalizes.) The Colt wasn't able to kill Lucifer and its sibling, The Equalizer, isn't able to kill God; Sam takes the brunt of the hit instead.
As God explains, the weapon "sends a wave of multidimensional energy across a perfectly balanced quantum link between whoever's shooting it and whoever they're shooting at." Meaning, God is exempt because his death would bring about the death of reality itself. The person pulling the trigger, however, is not.
In the first episode of Season 15, Sam is stabbed while protecting a woman and child from the harlequin ghost of John Wayne Gacy -- one of the many spooks the Winchesters previously put behind Hell's bars only to be set free by a wrathful Chuck. Castiel heals the stab wound and, seeing Sam flinch from the pain in his shoulder, offers to heal the injury he took from The Equalizer, too.
However, when he lays his angelic hand on the strange blemish, he finds he's unable to do anything to it. Castiel remarks that there's an energy around the wound he's never felt before. Then, even more disturbing, he sees a fleeting vision of a dark-eyed Sam in red lighting. With a twitch of the younger Winchester brother's head, Dean, in front of him, falls to the floor. "Sammy, please..."
The sequence is strongly evocative of the psychic powers Sam developed during Supernatural's first five seasons; forced on him by the Yellow-Eyed Demon, Azazel, in the hopes of fashioning the perfect vessel for Lucifer. Sam tried to use his telekinesis for good -- exorcising demons without bringing harm to human hosts. However, his addiction to demon blood -- which amped up his abilities -- sent him spiraling into darkness. And let's not forget, of course, that out of all of Azazel's Special Children, Sam ended up being the perfect fit for the ultimate evil.
When Dean takes a look at the strange mark towards the end of the episode, he notes the lack of an exit wound, meaning that all that "multidimensional energy" The Equalizer pumped into Sam is still inside him -- possibly poisoning him in some, as of yet, unknown way. Much like we saw with psychic Sam -- and soulless Sam -- it appears the final season of Supernatural is about to send Sam down a dark path again, one that could end in tragedy for both him and his older brother.
Airing Thursdays at 8 p.m. ET/PT on The CW, the final season of Supernatural stars Jensen Ackles, Jared Padalecki, Misha Collins, and Alexander Calvert.