This is based on opinion. Please don't list it on a work's trope example list.
Nightmare Fuel / Ghost Rider
Skinbender has an ability to transform anything she touches, which leads to lot of Body Horror.
The first issue of the All-New Ghost Rider has Robbie surrendering to what he thinks are the police...only to be shot a dozen times. His dead body is left beside a flaming car and then gets set on fire, too, completely consuming his flesh, until all that's left is bone. And then he wakes up screaming.
In the following issue, Mr. Hyde punishes a subordinate for a relatively small failure by tearing his eye out before giving it to his new second in-command as a warning...
Worst yet is Johnny cackling insanely in the midst of his agonizing screams. (Word of God said it's the Rider himself laughing with glee at finally being unleashed.)
His dispatching of the three elemental demons, complete with them screaming.
The first time he uses Penance Stare.
Every time he says LOOK INTO MY EYES.
Blackheart's occasional transitions into his devil form are a bit cheesy, but Mephisto's subtle morphing can make you shiver.
During Mephisto's introduction, we briefly see a shadow of his true self.
Every time Blackheart kills someone. He literally drains the life from them, causing their facial features to distort, their skin to turn blue, and black veins to etch themselves across the victim's skin (leaving them with an appearance not unlike Samara's victims in The Ring).
The scene where Blackheart shows up in Johnny's loft:
Blackheart: Not even close.
(Roxanne turns to see Mack — Johnny's pit crew leader and best friend — standing frozen in place. His skin turns blue, his eyes sink back in their sockets, and his lifeless body collapses to the ground, revealing Blackheart.)