Obbist
An Obbist is a creepy nerd who gets off on weird stuff. They usually hide in groups and can be taken down with a punch and a paper, but if it's an elite Obbist, you're in for a world of pain.
My cousin got caught by an Obbist in the library and had to hide under a table for an hour.
That Obbist in my class follows me around like a lost puppy.
I texted my friend: 'Watch out, there's an Obbist in the hallway.'