There is a danish book titled “Den Der Falder” (“The One That Falls”) of Michael Larsen that tells a story about This Man. It a thriller published in 2020.
This is a Synopsis:
“Julie Viver suffers from sleep paralysis, and the man who chases her in her dreams is terrifying – and real! But an advertising man claims that the man Julie is seeing is a big hoax that someone made. The problem is, Julie started seeing the mystery man before the ad man did his trick…”