The Lovecraft story beginning “I am writing this under an appreciable mental strain” is “Dagon.” Its opening presents a desperate narrator preparing to die, immediately framing the tale as a final confession written under the pressure of trauma, morphine dependence, and impending suicide.
The narrator recalls escaping from a German sea-raider during World War I and drifting alone across the Pacific. After the sea mysteriously recedes, he finds himself stranded on a vast, foul-smelling seabed. There he discovers a gigantic monolith covered with unknown carvings and witnesses a monstrous sea creature rising from the depths.
Although the title invokes the ancient deity Dagon, the creature in the story is not explicitly named Dagon. The narrator later researches the Philistine legend of Dagon, the Fish-God, which supplies the story’s title and its biblical-cultural association. This distinction is a common source of confusion in discussions of Lovecraft’s mythos.
“Dagon” was written in July 1917 and first published in The Vagrant in November 1919. It later appeared in Weird Tales in October 1923 and is often regarded as one of Lovecraft’s earliest major cosmic-horror stories.