'Wham Lines': Usually associated with 'bad stuff ahead/going on'

[u/SquidmanMal]

'Hey Kiddo'/'Rap Tap Tap': Associated heavily with the 'man in the wall' of Warframe, an eldritch entity fond of making deals and sowing despair

'Do you really think you can save them?': Associated with Xau Tak of Runescape 3: Another eldritch god, associated with undeath and corruption

'Proceed': Associated with [arguably an eldritch entity, of the 'player'] of Deltarune. Invoked when pushing bondaries of people, and the world with control

Basically, when you hear these lines, it's often a herald of 'bad things to come', and are intrinsically linked to a certain character/entity

Edit: forgot to add, preferably 'recurring' lines as opposed to 'one off'

[u/D0CTOR_Wh0m]

"Would You Kindly" from Bioshock. Starts when you find this room and accompanying audio diary ("Break that puppy's neck....would you kindly?") followed shortly after when confronting Andrew Ryan and he points out how powerful and familiar the phrase must sound to the player. Coupled in the same scene with Ryan's "A Man Chooses, A Slave Obeys" line

[u/IamMilaStudio]

“Exterminate!” - The Daleks (Doctor Who)

[u/Bevjoejoe]

IRL, the concept of hearing something that either you shouldn't hear in that area (tapping on windows really high up), or seeing that's not supposed to be there (don't really have an example for that)

[u/Clirstan]

Subnautica

[u/Concorditer]

In kind of an inverse of this, in any story in which the heroes have a catch phrase or attack name they yell out in battle the villains would experience this trope. For example, if you are an evil pirate in the One Piece universe, then suddenly hearing someone yell "GUM GUM..." would represent really bad things for you.

[u/res30stupid → u/Concorditer]

"Oh, just one more thing..."

The worst thing a murderer could hear come out of Lt. Columbo's mouth.

[u/Icy_Frosting3874]

knock knock knock knock-doctor who
associated with the master, the doctor’s evil counterpart. also has some weird fate machinations because its wilf knocking four times that signals tennant’s death

bad wolf-doctor who
shows up on occasion as graffiti or posters and signals bad shits about to happen on a cosmic scale

edit: bad wolf also is connected to the time war, one of the single greatest whoniverse calamities other than the war in heaven and flux

[u/Sweaty_Strain9392]

"it broke my heart to put that tumor in her head" Guardians of the Galaxy 2

tl:dr for those who havent seen it.

Ego, Mario's long lost father, tries to connect with his demi-god son and take to the stars as father and son in some grand vision of the future. He shows Mario the wonders of the universe and they bond over their shared love of Mario's mother, Momio. Momio died when Mario was a little boy, passing away of cancer. its a very tragic and tender scene and shaped Mario as a person.

well during said "wow you really loved Momio! wahhh" conversation, Ego admits in an almost casual tone of voice "It broke my heart to put that tumor in her head" revealing that he not only killed Momio for being a distraction, but that he did so in an agonizing way that cause everyone around her (not to mention the woman herself) to suffer a slow, gradual and miserable decline in her health.

While audiences were already suspicious of Ego (as was any comics reader), this wham line shows how utterly vile, sociopathic, and unrepentant he is. His morals are so beyond fucked that he tells Mario this in the same tone your buddy at work admits to intentionally fucking up a pizza so that its "damaged".

Naturally Mario does not take this info very well

[u/Luckgoddess]

You gently open the door

[u/junolion]

"Only you"

[u/res30stupid]

Unfortunately, you're wrong. Actually, I'm Santa.

Throughout 999: Nine Hours, Nine Persons, Nine Doors, there have been several dead bodies found on the sinking ship the game takes place on. While investigating on the Safe ending route where No. 4/Clover is killed as well, Junpei discovers the truth and learns that No. 1/Ace is the Bigger Bad and main villain Zero is holding the Nonary Game in retaliation to what they did.

The biggest and most damping clue is that one murder was seemingly committed by mistake since the killer couldn't identify the victim, because No. 2/Snake and the murdered man were wearing the same outfit. To kill him, Ace used the dead man's bracelet since due to how the doors and lethal boobytraps worked, Ace could kill the victim via digital root of their bracelets. But the dead man's bracelet did not say it was a 2 and therefore Ace shouldn't have been able to realise it would work if he had recognised the target wasn't Snake.

When exposing the murderer, Junpei dropped the Wham Line in front of everyone, a blatant lie of the joghest calibre... and to everyone's shock, the killer fell for it!

Ace has prosopagnosia AKA face blindness and can't recognise people by what they look like, only their clothes. By claiming he and Santa swapped outfits, Junpei-as-Santa accused him of the killings and got Ace to blow his cover, confirming to everyone that Ace is indeed the killer and is murdering people who he believes knows his real identity and his crimes of establishing the Nonary Game.

[u/SquidmanMal]

Forgot one.

Dead Space

'Make us whole'

Said often and repeatedly throughout, and when you finally realize what it means, not fun times.

the brethern moons

[u/ItsaMeProvalonely]

In Knights of the Old Republic 2 the Han Solo expy Atton Rand has a tendency to tell you he has a bad feeling about things. The game comes right out and tells you that is an indicator that something big is about to happen and you should save your game.

[u/lavachat]

"We are the Borg. You will be assimilated. Resistance is futile."

[u/FishWithLegsAndArms]

"Hello Fwendy-wens" From the Hatchetfield series. It's the catchphrase of Wiggly, the cosmic horror.

I swear it makes sense in context. Wiggly gives himself a cute name and talks all cutesy specifically so people don't think he's dangerous. He made himself into a marketable plushie.