"The Thing on the Doorstep" by H. P. Lovecraft is a horror short story written in August 1933 and published in January 1937. Daniel Upton confesses to killing his best friend Edward Derby, insisting he's not a murderer. Derby's marriage to the occult-obsessed Asenath Waite brings disturbing changes—he exhibits abilities he never learned, speaks of sinister body possession, and hints that Asenath's deceased father may still be alive. As Derby's behavior grows increasingly erratic, Upton confronts a terrifying truth about souls, bodies, and something waiting on his doorstep.