Place this clip at the start of the attack sequence, before any chase music builds. Follow it with the FNAF jumpscare scream for the reveal hit, then add the Roblox Oof sound when a survivor gets caught to close the sequence cleanly.
About this sound
This is a 3.6-second voice clip of 1x1x1x1 delivering the phrase Mass Infection in a low, threatening announcement. It feels tense and ominous, like a warning that an attack is starting rather than normal dialogue. The line comes from Forsaken, the horror experience where 1x1x1x1 appears as a killer.