All the predators are prone to this, having More Teeth than the Osmond Family and being Always Chaotic Evil from the mice's perspective. But the one that takes the absolute prize is the Big Bad and the page image, Erebus the Mad Alpha. Helps that he actually has a raven cult worshipping him as the bringer of the end of the world.
The reveal of what happened to the world: Societal breakdown followed by nuclear war, described as three great wolfpacks. The image of a nuclear fireball appearing as a terrifying Animalistic Abomination will burn itself into your brain, but that isn't even the worst. The Sky Wolves - shadowy figures representing radioactive fallout - are even worse. Erebus and his pack are the third, and they carry plenty of Nightmare Fuel of their own.
After Titan dies, Wix has recurring nightmares of him trying to kill him. Only in his nightmares, the cat is even bigger than before and is constantly on fire.
Resher's final solution in Chapter 9. Seeing no other option, Resher orders his goons to set the house on fire and tries to take all the food and supplies away, telling them all that they can either join him or die. The house inadvertently catches on fire before he gives the order, and his first response is to leave everyone to perish.
Resher chasing down and almost killing Pict. At this point in the comic, his plans have failed, his goons are dead, everyone knows about his schemes, and the house he's in is currently burning down. He is so committed to petty vengeance that he'd rather risk his life murdering a sole mouse out of pure spite than getting himself to safety.
