Deep Night (1991)

Original title: Notte profonda

A depressed writer of horror comics finds a strange artifact, a small pyramid, while cleaning up a bar. The pyramid is a sort of puzzle and once opened it spawns evil, invisible entities which silently haunts the protagonist by possessing objects in the house during the night, while he is asleep. The paranormal manifestations become more and more invasive and frequent...what's the secret behind them and the pyramid? Our hero will discover it, but he will pay a very high price for it also.