The Hoodies lay seige to a school by night and go on a murderous rampage, capturing a security guard and locking him in a dumpster before setting him on fire - they proceed to break into the school and murder the librarian before terrorize the protagonist.
The Hoodies, like many horror antagonists, are driven purely by bloodlust and have no redeeming qualities whatsoever, despite their young age, in fact they seem to take sadistic joy in senseless murder and target each victim at random (this references a real-life phenomena known as "happy slapping" - in which youths attack people at random, often for thrills).
There are at least four Hoodies. One of them was killed by Robert Anderson with their own knife in self-defence, and another was bludgeoned by Kate with a fire extinguisher (although it's unknown whether or not the latter Hoodie survived it). Robert escapes the school alive, with his daughter Kate wounded by one of the Hoodies but alive, while Robert's wife Helen was left wandering the school's hallways alone, unaware of her potential fate at the Hoodies' hands.
- Security guard (burned alive inside a dumpster)
- School librarian (ambused by thugs in library)
- Gym teacher (attacked by the Hoodies with crowbars, horribly disfiguring her face and leaving her weak and bleeding out; afterwards left crawling through the hallways to slowly die)
- Head teacher (killed by bludgeoning with a fire extinguisher, leaving half her face gruesomely destroyed)
- Jake Eaves (a student, wrapped in barbed wire by sadistic thugs)
- Gary (member of the auxillary staff - electrocuted)
- Female police officer (thrown down stairs)
- Other police officer (killed by crowbar)
- It was never revealed in the film who (or what) the Hoodies are or why they committed their monstrous acts of pure evil, although viewers have put forward a few theories. It is thought by some that the Hoodies could have something to do with the pupil who assaulted Robert at the beginning of the film for giving him an F grade. A few have suggested that the Hoodies probably aren't even human, judging from their seemingly-motiveless acts of monstrous evil and their unusual level of strength in the film.