Glitter. Once you use it, it's on you, your clothes, and your belongings forever.
"God damn it, it's been months since I used any glitter and there's still art herpes everywhere!"
The glitter you get on you in the art room. Gets all over your hands, face, and EVERYWHERE... and when you check your hair five years later, it's still there.
Person 1: "Dude, there's glitter in your hair."
Person 2: "Yeah, just got some art room herpes. It won't go away!"