Being an example of Dark Is Evil, Vlad Vladikoff the vulture could definitely qualify.
And in the movie: Katie. Seriously, some of the faces she pulled will haunt your dreams.
Had it not been for JoJo's epic "YOPP!" he and the entire Whos would've died. Including his 96 younger sisters.
When Vlad drops flower carrying Whoville, we get a close up of the building being crumbled. Luckily, it turned out alright. But still, it's very unnerving.
Pretty much the entire story. Horton just wants to listen to his shiny flower and the other animals just cannot deal. Shades of George Orwell.
When Horton is described as "more dead than alive" while searching for the clover.
Vlad wanting to eat Rudy as compensation, and his mother telling him to be quiet while she thinks it over. Having your mother openly mull over whether or not to sacrifice you, even for a moment, is definitely nightmare fuel.
Hell the Sour Kangaroo altogether is a lot more wrathful and malicious in the film, having a thinly veiled rage in nearly every scene she is in. Look how every animal, even her own son, fears her. Even her original more well intentioned renditions have a sinister edge to them, she's essentially The Queenpin of the jungle, and if she finds someone acting remotely in a way she finds illogical or unstable, she will send the other animals to discipline you or in extreme cases, restrain and cage you up like a madman.
The roping and caging of Horton is even more intense then it is in the 1970 special or book. Once the kangaroo has the clover, she gives Horton a sinister smile/giggle as she snatches it away from him. Once she is at the beezlenut pot, she gives him a Death Glare as she slowly drops it in. Thankfully Jojo is able to prevent his town’s death from happening, because if the who’s had died (which is a pretty horrifying concept in it’s own right) one would dread to know what would have happened to Horton once the who’s had been boiled
