I’m as certain as I can be this is not The Craft. It’s about some (teenage) girls, learning witch craft as a way to gain power in school. The scene I remember was all the girls having dinner together, and the course is snails. One of the girls (I think she was the “put upon” girl) shows her total disgust at the thought of snails and slugs. Cue meaningful looks from the other girls. She goes back to her room, and finds one slug in her bed. It disappears, so she relaxes. She goes to bed and suddenly she’s covered in slugs and snails. One goes inside her mouth and you see her biting down on it.
This’ll be an easy one for you guys, I’m sure, but Googling just brings up “The Craft” and “Slugs”.