Nightmare Fuel / Thud!

  • The Summoning Dark.
  • And In-Universe, Vimes possessed by the Summoning Dark rapidly becomes this to the dark dwarfs at the end.
  • "A short dark figure was at the top of the stairs and disappearing into the nursery."
  • "They killed my son." "I'm sorry, commander, but it's true. I don't think Gunder Ironcrust was interested in the politics, you see. He just took a job at the mine because he wanted to feel like a real dwarf and work with a shovel for a few days." "They left him to the mud...any help you need, we will give. Any help. But when you find them, kill them all."
  • Helmclever's death, if only for how quickly and quietly it happens. One second, he's alive, and then Vimes accidentally knocks over the candles. A few seconds of darkness later, he's dead, and the Thud pieces on the board have formed the shape of the Summoning Dark. All because Vimes lost his temper at Colon. And while he certainly didn't touch Helmclever, he didn't touch the dwarf that went after Sam, either...
http://tvtropes.org/pmwiki/pmwiki.php/NightmareFuel/Thud