The Thing on the Doorstep

"The Thing on the Doorstep" is a short story written by H. P. Lovecraft, part of the Cthulhu Mythos universe of horror fiction. It was written in August 1933, and first published in the January 1937 issue of Weird Tales.
Two novels suggested as inspirations for "The Thing on the Doorstep" are Barry Pain's An Exchange of Souls (1911), about a scientist's invention that allows him to switch personalities with his wife, and H. B. Drake's The Remedy (1925; published in the U.S. as The Shadowy Thing), in which a character with the power of mind-transference comes back from the dead by possessing the body of an injured friend.