Is it normal that my former friend used to do this?

So I used to hang out with this girl who used to do really creepy things like if we invited her to hang out in a group she'd take pictures of us and secretly record us. She'd actually record with her phone and hold the phone in front of her to record our conversations and get us all filmed... why would she do this? She also used to fantasize about hanging out with certain people and once she was friends with you she was like obsessed with you...