Don't forget the Wooden Mask Salesman. The way he appears out of thin air behind Herpy, that creepy-ass grin (which changes into a freaky angry face after her learns Daring put the mask on) and his cryptic phrases. Good thing he's an ally ...or is he?
Daring-Do herself gets into quite a few insanely dangerous situations, especially in "The Legacy of Nightmare Moon". *shudder* It's a good thing Herpy was there to save her when he did...
That was just Alicorn's Shadow. When he makes his return as the Dragon with an Agenda in Temple of Nightmare Moon. He's still his sociopathic self. Hell, he even admits to being one to Herpy.
And then we have him killing Nagridge. Sure, she was one of the most hated characters, but it was heavily implied that Mareton snappedherneck, for foals!
It's rather unsettling whenever Coco Pie switches over to her Chocolat' mode. At times, Chocolat' can come off as even more psychotic than Ahuizotl. Good thing she's one of the good mares? Right?
That gold thing called Koloktos. It's so bizarre looking, I mean, how is it able to walk around on two legs without falling over? It has many arms, but none of them are used for walking, instead for carrying swords. It's very creepy when you think about it.
At least Minotaurs use their tails as counterbalance.
To bring the point home, he has a record collection filled with nothing but the sounds of ponies screaming. Hours and hours of nothing but Ponies screaming, and he enjoys it. That's nothing to say about the potential
This fact becomes even worse when Fridge Horror strikes: what did he do to get those sounds to put on the records in the first place?!
Another fun fact? Rumor is, he turns ponies into glue.
He may have a a lot of funny moments, but he is still definitely creepy-possibly the worst thing about him is that, while he's on the loose, every time somepony dies, he absorbs their immortal soul, meaning he has total control over what happens to it. So what does he do? He places it in a dark dimension of his own creation, where it will be tortured for all eternity. What's even worse is that he plans each torture specifically to match each pony, giving them some sort of ironic torture based on their Cutie Mark, or just whatever their special talent is if they're a creature without a Cutie Mark, like a griffon. He comments that sometimes when he's bored, he brings popcorn to one of those dimensions at just sits there and laughs at the ponies being tormented.
Not to mention the courtyard of the castle-it's covered in spikes, and each one has a screaming head impaled upon it.
Think about this: At one point, he wears the Wooden Mask, and we all know what that did to Daring. But Krastos? He is so evil that he isn't affected at all.
The Golden Key. This key has the power to force anypony to become some sort of Automaton, whose goals are to create more Automatons. By the time chapter 4 ended, the Golden Key Automatons had already taken a village.
The Redhorn Cult. An insane cult of ponies that worship an evil God and appease it by sacrificing foals.
Plus, they also resurrected Koloktos as a minotaur-headed abomination that can breath fire. And it doesn't just stop there, there is the part where Koloktos uses its flames to incinerate the Redhorn Cult leader, Lord Bullrush, to death.
It doesn't help that the story described him as "... shrieking in unfathomable agony while the violet inferno engulfed him." Brrr...
The Changeling attack in Return of the Fire of Friendship. And our heroes just barely manage to prevent the invasions of Baltimare and Fillydelphia.
