I'm going to ghost a girl after she scared me.
How did she scare you? Did she say do something really bad?
No, she smiled at me all creepy-like and said "don't worry, it it's not dangerous" in a weird voice.
That sounds really creepy, and I understand why you might want to ghost her, but I don't think that's a good idea. You should let her know you aren't interested in talking to her instead, so she doesn't think something happened to you.
If I stop talking to her altogether though I would feel more comfortable.
While what she did was wrong you should tell her how you feel. She might not be aware of what happened and could learn from the experience.