Arioch the ???

WIPPITY WIPPERS

Pied piper, eats children/ babies. Keep Arioch's crazy-face. Lost children, lost her uteris to... something. Mix with folklore of witches/ whatever spiriting away kids?

Infected?

Don't make a zoro. It'd just be Dee again |D

Milotic? Dragonair? Prefer something with hands/ claws to grab.

... What about a Sneasel or a Weavile

What about a Scizor they can grab with their pincers.

Make it a fairy type!
In classical mytholgy this is the sort of thing that they'd dooooooo.
(Or a Baba Yaga, IDK)
EDIT: in fact, I was working on a WIP similar to this myself, I can share some of my ideas if you want some addition inspiration.

Gardevoir with it's fairy type would work. Use Hypnosis to draw children towards it then when they fall asleep eat them.