A concept named after Ash Williams by the Youtuber "The Librarian". It is the point at which horror games lose the ability to scare players after the player was exposed enough to the game and it's contents. It is frequently crossed in the FNaF games, where after enough deaths, the animatronics become an annoying nuisance, than a terrifying enemy to look out for.
Guy 1: I can't keep playing man, this game is too scary.
Guy 2: Don't worry, it will reach the Ash Threshold soon enough and you'll be fine.