Ahmanet herself, before she regenerates fully, is horrifying to look at; she's pretty much a hybrid of a bandaged Slender Man and Stringy-Haired Ghost Girl in regards to her movements.
The way she sucks life out of her victims to regenerate herself, leaving them as rotten corpses and raising them as zombie mooks. And the transformations she had, when she regenerate her flesh, fluids and skin from inside. In contrast with Imhotep, Ahmanet looks really like a mummy. A dessecated, thin corpse back to life.
Her mummified body is twisted, basically her torso is twisted and she walks as a spider.
If you think that it's better that she wasn't devoured by carnivorous scarab beetles like Imhotep, she was completely alone in that sarcophagus, as her body rot for 5000 years. It's implied that this time made her mentally ill and mad. It's implied that the oniric desert that Nick see in his first vision after free Ahmanet, is the place where she had been 5000 years. But imagine 5 millenia completely alone, under a hot sun, walking barefoot across the hot sand forever.
Her double irises. There's just something inherently wrong about them.
And then Nick gets double irises too, courtesy of Set...
Ahmanet has an insidious, pervading hold on Nick - his gaze is continually drawn to her, she teleports him to her simply by beckoning, and no matter how desperate he is to get away from her, he unknowingly drives straight back into her clutches. And all this because he broke an decrepit piece of ancient rope. Brrr.
Vail:[undead;matter-of-fact] You can't run. You can't escape.
Set's movement, for lack of a better word, is unnerving.
Nick regularly has visions of a dead Vail, and Vail appears as he was just before his death, with bullet holes in his livid body and one of his eyes completely rolled upwards.
Nick also gets swarmed by a horde of rats as a half-mummified Ahmanet scuttles towards him. But, good news! It's a hallucination. Bad news: he's actually standing in the middle of a busy London road, cars screaming past him.
Mr. Hyde is made quite a bit scarier by how the physical change is minimal, dependent largely on Russell Crowe's performance to sell his transformation from a dapper gentleman to a feral monster. Crowe is very much up to the task.
Hyde and Nick's fight also involves Hyde pinning Nick on his side and attempting to dislocate his lower ribs. You see them move weirdly as Hyde gleefully yanks on them, and Nick's screams reach a new level as the pain hits. Ugh.
Ahmanet's entire speech to Jenny within Prodigium.
Ahmanet: The old gods? Your language is simple. What you truly wish to know is what lies beyond the veil of death. To know what I have seen. And you will, when... I... kill... you. (evil smirk)
and Stringy-Haired Ghost Girl in regards to her movements.