Preacher's renegade angels DeBlanc (Tom Brooke) and Fiore (Anatol Yusef) need to get back the thing that's taken up residence inside of Jesse Custer (Dominic Cooper), or else they're going to be in big trouble with the man upstairs. They tried to cut it out with a chainsaw, but that didn't work, thanks to the intervention of Cassidy (Joseph Gilgun). So in the last episode, they sat down with Custer and laid it out for him.
They explained that they know he's been using the powers the thing inside of him has granted him, but that power is too dangerous to be out in the world, so could he please give it back? Custer doesn't understand what they're talking about, since he's never seen them before in his life.
But in the bloody clip above, he finally starts to comprehend. You can see it on his face — he's like, "I don't know what's happening, but whatever it is, it's much less human than I thought."
See more on the next Preacher, Sunday at 9/8c on AMC.