The Curse of Yig
by H. P. Lovecraft
In 1899, upon arriving in Oklahoma, a couple learn about local legends surrounding a "snake god" called Yig, which takes vengeance on anyone who kills a serpent by either killing them or turning them into a half-snake monster. The husband has an intense fear of snakes, and his wife kills a nest of rattlesnakes at one of their campsites. The husband is horrified by the thought that Yig will take vengeance. After building their cabin, the husband is insistent on practicing various rituals from the native tribes to keep Yig away, grating heavily on his wife's nerves. In fear, the woman kills her own husband in the dark, thinking he is Yig. She is taken to an asylum, and dies there... but not before giving birth to a half-snake creature.