Mr Hendrix said that on one night in May, 1981, he crept downstairs as a 9-year-old in the hope of gorging on a midnight snack.
"All of a sudden I heard a fork click on the counter. I froze. The microwave clock light showed the outline of a man sitting at our kitchen counter," he wrote.
"He couldn't see me, but I saw him: a skinny guy, eating our leftovers, and drinking our milk from the carton."
Mr Grady explained that by the time his parents got downstairs the intruder had fled and "the kitchen was empty".
"Everyone said I read too many horror comics so they blew off what I said.
"I started tracking the position of everything in the kitchen. One day the paper napkin holder was on the wrong side of the counter. Another day a mug was in the sink that was NOT there the night before.
"My bedroom door didn't lock so I kept a steak knife under my pillow. I must've stabbed myself in the hand 1000 times checking to make sure it was there."
Three months later the man returned, but in an even more terrifying ordeal.
At the end of the month, the family began to notice a smell in the house.
"One night, rice fell out of the vent over my bed. Maggots. The A/C people said something had probably crawled into our vents & died."
It gets creepier.
Mr Hendrix is a US based author of titles such as "My Best Friend's Exorcism" and as Pedestrian's Josephine Rozenberg-Clarke wrote: "Look, Grady Hendrix IS a writer, seeming to specialise in horror, so I think I might take this with a giant grain of salt and pray to the universe it isn't true"