Horrorstör is a 2014 horror comedy novel that was written by Grady Hendrix and illustrated by Michael Rogalski. The novel was released in paperback on September 23, 2014 through Quirk Books and is set in ORSK, an IKEA-esque store that has been experiencing supernatural phenomena. The audiobook release was narrated by Tai Sammons and Bronson Pinchot. The book's events take place largely over the course of one night in ORSK and the story is accompanied by illustrations of ORSK products, which grow more sinister as the book progresses.

Grady Hendrix is an American author, journalist, public speaker, and screenwriter known for his best-selling 2014 novel Horrorstör. Hendrix lives in Manhattan and was one of the founders of the New York Asian Film Festival.