Atop the Fourth Wall: The Spoony One hearing the noise that the Entity makes when it's claiming one of its victims. Then the creepy laugh that follows it. When hears it, he actually says the trope name word for word.
Even worse when you realize that IT'S NOT JUST A RANDOM NOISE. Hhhhhhhhhhuuuuuuuuuuuuuuuuuuummmmmmmmmmmmmmmaaaaaaannnnnnnnnn...
In Diamanda Hagan's review of Sextette, she dubs over Dom Deluise's musical number with "something a little more pleasant". In the ending credits, she reveals what the noise was; an angry Tasmanian Devil.
An interesting variation, because the story is in second person, you the audience is the main character hearing the sounds.
Also features cloth rustling sounds, things in the dark, and various other stock Horror movie sound effects. Constantly.Until right at the end. The Narrator actually comments at that point that this is the first time it's ever been ''completely silent'' since you woke up in Razor Hill. Meaning the sounds were so constant, you mentally tuned them out to the point where you don't realize they were still there until they are gone.