The Shambler from the Stars

The Shambler from the Stars is a horror short story written by Robert Bloch and first published in the September 1935 issue of Weird Tales. It was later included as part of his first published book, The Opener of the Way (1945), and his 1994 collection The Early Fears. As a Cthulhu Mythos tale it is notable for introducing the forbidden tome De Vermis Mysteriis (Mysteries of the Worm), and being a prequel to Lovecraft's own short story The Haunter of the Dark, which was dedicated to Bloch.

-- Wikipedia