Unmarked spoilers are ahead, per Spoilers Off rule.
Barry's simultaneous evisceration and rape of Rayflo. Part of it Barry's sitting there licking a piece of Raylfo's spine that he removed before he puts it back by shoving it back into the gaping hole in Rayflo's chest. While still en flagrante.
What Father Kazan turns into, and the ensuing fight.
In Chapter 15, we get a lovely scene of Barry getting decapitated and then said decapitated head blinks a few pages later. Then, it gets up.
Taken even further in Chapter 18, when Barry's bloody, decapitated head gets up and starts talking while the rest of him walks over to reattach it. Also Charley rips Barry's body a new one only for Barry to regenerate himself multiple times, taking the Squick factor up a notch.
