The tune that plays when Freddy catches you when the power runs out. If the night doesn't end before the tune finishes playing, then see directly above.
When you stare at one of the animatronics through the camera, sometimes you hear a disturbing ambient noise along with the above mentioned camera screw. This noise can last even after you look away from them.
The pained "breathing" Bonnie and Chica make if they've managed to sneak into your room while you're still looking through the cameras. You're doomed the moment you pull the monitor down. Or they do it for you.
A sound effect sometimes plays to indicate an animatronic is on the move. If you hear running footsteps, you'd better think fast.
If you try to close a door after Bonnie or Chica have slipped into the office, you'll get an error sound instead. At that point, your death is almost certain.
The sound of everything turning off. Made worse by the fact that it's possible to win after that, making it potentially a terrifyingly suspenseful Hope Spot too.
Freddy's laugh, serving as a warning he's changed position, and growing progressively louder as he nears the Office. Especially if the game is set to 4/20 mode, where Freddy refuses to quit moving, flooding the whole pizza place with the incessant sound of his evil laugh.
From Night 4 onward, a garbled noise will play whenever you check Bonnie and Chica at the West Hall Corner and East Hall Corner, respectively, accompanied by them twitching their head like crazy. This is the same noise that plays during the "IT'S ME" hallucination, as well as the supposed backmasked message from the Night 5 phone call.
Occasionally, clowny music will faintly play in the background of the game. This is somewhat uncommon, but it seems to happen more when Bonnie or Chica are approaching their respective hallways. The second game suggests that this music is playing for a very good reason.
"Da-da-dum-dum da-dum-dum-dum-diddly-dum dum-dum-diddly-dum dum-dum-diddly-dum-dum-dum-dum-didlly-dum-dum-dum-dum-dum..." A warning that Foxy is active.
The first game's jumpscare noise was derived from a woman's scream (SCREEEEE-). The second game had the animatronics emit a mechanical roar instead (REEEAAAAH-). This game? A horrific zombie-like screech that sounds NOTHING like what a robot should sound like (RHUIIIIAAAAH-). This turns out to be appropriate, as the Murderer's corpse is inside Springtrap.
The grating buzz that plays throughout Phantom Puppet's hallucination.
The awful sound, reminiscent of a dial-up modem, that assaults your ears every time the Purple Man destroys an animatronic in the end-of-night minigames.
The low whining noise that plays when one of the animatronics are inside or near your office. Unlike the previous game, though, it gets louder depending on how close the animatronics are, and you might not catch on to the fact that it's a sound cue to their presence because it doesn't really stick out from the rest of the sounds in the game. This noise gets worse thanks to the implications of The Twisted Ones. This high-pitched noise could be a mind-altering device that causes you to see things. Seeing things? Like, maybe, the Phantoms, for instance?
As per usual, the nightmare animatronics' signature screech counts as this — but this time, it literally sounds like Hell because it combines elements from all three of the previous screeches: the sound of a child screaming, a mechanical reverb effect, and an animal-esque roar. In the latter's case, this is not a roar of pained agony, as is presumed with Springtrap, but one of pure hatred and anger. The game makes this even worse by forcing you to listen for the animatronics rather than watch for them via cameras.
If you encounter Nightmare, his jumpscare is accompanied by a sound that befits both his name and this trope's name — it sounds like the distorted moaning and wailing of spirits. Ditto for Nightmarionne in the Halloween Edition.
In night 2, you have to navigate a dark, eerily quiet section where Ballora is hunting you down. Whenever you hear Crumbling Dreams playing, keep still. She's nearby, listening for your footsteps.
The audio tests that Cassette Man uses when salvaging the animatronics. They have small hints of being a heavily distorted Freddy's theme from the first game.
As with every other game in this series, the eardrum shattering screech that the animatronics make when they jump scare you certainly qualifies. BWAAAAAAAAAAAAAAAAAAHHHHHHHHHHHHHH!!!!!!
that sounds NOTHING like what a robot should sound like (RHUIIIIAAAAH-). This turns out to be appropriate, as the Murderer's corpse is inside Springtrap.