Asking a question of witches because that's the only thing that kinda makes sense. I've tried to convince myself it was nothing, but...

Why would a girl, late teens, early 20's, sneak up behind someone, late at night (maybe 3am) and sprinkle tiny bits of torn up paper on their shoulder? The paper was pink, and the shoulder was left side.
I feel a bit silly asking this, but it keeps picking at my brain. Given the weird things people are into, I'm asking even if it does feel silly. 🤷‍♂😆