Eldritch is a word meaning something otherworldly, weird, ghostly, or uncanny.

Although a fairly old word, Eldritch has had something of a revival being strongly associated with Lovecraftian Horror, Dungeons and Dragons (since Eldritch Wizardry (published in 1976) was written by Gary Gygax and Brian Blume), and horror fiction that takes inspiration from one or both of the other examples.