FINAL EDIT: @nomad@infosec.pub found it, it’s Roswell Conspiracies, thank you everyone!

The white-haired females would frequently meet at a Stonehenge-like monument where there was also some kind of a portal. I also only remember this one specific scene and nothing beyond that:

(a bit graphic, click to show)

There are men who are restrained, and their mouths are being held open. An elderly man places a large egg on top of a ramp, and the lower end of the ramp is connected to the mouth of one of the restrained men. The egg eventually hatches, and a big snail emerges from it. The snail then slowly slides down the ramp and enters the mouth of the man, who is forced to swallow it. As a result, the man is immediately brainwashed and gains additional physical powers and will serve as an additional soldier for that old man.

EDIT: the art style resembled that of X-Men Evolution

    • AlmightySnoo 🐢🇮🇱🇺🇦@lemmy.worldOPEnglish
      1·
      1 year ago

      Edit: I found it online, and while there is a scene with witches at Stonehenge, I couldn’t find anything with slugs. Probably not what OP is looking for

      Yes I also just watched that scene, definitely nothing to do with the description.