Horrors are a broad creature type associated primarily with blue and black, encompassing everything from eldritch monstrosities to creatures born from nightmares. Horror decks commonly overlap with mill, exile, graveyards, and stealing opponents' cards.
Nemesis of Reason mills huge chunks of a library whenever it attacks, while Zellix, Sanity Flayer converts milling creatures into additional Horrors. Spellskite demonstrates that not every Horror needs to be particularly horrifying to be useful.
