From Beyond

"From Beyond" is a horror short story by American writer H. P. Lovecraft. It was written in 1920 and was first published in The Fantasy Fan in June 1934 (Vol. 1, No. 10).
The story is told from the first-person perspective of an unnamed narrator and details his experiences with a scientist named Crawford Tillinghast. Tillinghast creates an electronic device that emits a resonance wave, which stimulates an affected person's pineal gland, thereby allowing them to perceive planes of existence outside the scope of accepted reality.