Predator's Brutality winpose has him cloaking and walking off into the background. When performed on the narrow bridge-like Kove, Krossroads or the Pit X stages, however, when Predator walks into the background, his spaceship can be seen briefly decloaking and flying into the sky. This is because the Predator would otherwise be walking and logically falling off of the stages.
Contributed by MightyKombat
In February 2015, Warner Bros was given a small window of permission from Todd McFarlane to use Spawn in its games. However, Ed Boon was unaware of the offer two months later, despite revealing that Spawn was discussed as a potential guest character. Spawn would later be added in Mortal Kombat 11.
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If Alien’s victory animation or the Alien Baby brutality is done on the Predator, the Chestburster is a Predalien from the Alien vs Predator franchise.
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Leatherface's Fatality "Hook and Sinker" is a reference to Spoiler:Kenny's death in "Texas Chainsaw".
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Leatherface's victory animation when he defeats his opponent without performing a fatality is a reference to the original film where Spoiler:Leatherface furiously flails his chainsaw after failing to recapture Sally.
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Alien's first fatality, "Killer Queen" is a recreation of the scene wherein Spoiler:Xenomorph Queen dispatched the android Bishop in the film "Aliens".
All of the characters who only appear as opponents in Story Mode have a bullet for whenever they get shot by Erron Black's X-Ray move. Normally these are stored in character DISM files, but the Story Mode characters have their bullets located within their character packages.
Contributed by RyuHane
When Bo' Rai Cho faces Reptile, Bo' Rai Cho will sometimes state before the fight that he sensed a Zaterran, to which Reptile corrects "the last Zaterran". Bo' Rai Cho will then remark "No, there is another".

This is a reference to the movie Star Wars - Episode V: The Empire Strikes Back, when Yoda says the exact same line as Luke Skywalker is leaving Dagobah.
Contributed by MrJohnnyOTGS
In the release of Mortal Kombat XL, one of the new trophies/achievements is named "Fox Finish" which requires you to win a match with the opponent stepping on Caltrops.

This is an homage to top MKX player Dominique "SonicFox" McLean and his common practice of closing out intense matches with Erron Black's caltrops.
Contributed by AkiraTheWarrior
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In an intro between Bo' Rai Cho and Predator, Bo' Rai Cho will call the Predator "One ugly motherfucker", a reference to the line spoken by Dutch after the Predator is unmasked in the original 1987 Predator film.
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In one of his intro dialogues with Alien, Johnny Cage will shout "It's game over, man!". This is a reference to the iconic line shouted by William Hudson in the movie Aliens.
After winning a round, Predator's laugh will mimic the opponent he is currently fighting against. While fighting another Predator or Jason, however, he will instead mimic Billy's memorable laugh from the original Predator films.
In one of the intros in a Shinnok mirror match, the second Shinnok mentions that he failed to kill him "at the Pyramid." A reference to his ending in Mortal Kombat Armageddon in which Spoiler:Shinnok sends a clone of himself to defeat Blaze.
Originally Mortal Kombat X was planned to have XBOX 360 and Playstation 3 versions, produced by High Voltage Software, but those versions were eventually cancelled and full refunds were offered for pre-orders.
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The gory sound effects were made by squishing a gooey substance in a bowl with a toilet plunger and smashing lots of various fruits, vegetables and nuts with a hammer.
Contributed by ProtoSnake
The Terminator and Michael Myers from the Terminator and Halloween franchises, respectively, were considered as fighters for the game, however, according to the series creator, Ed Boon, the ideas never went any further.

Boon told IGN about the characters, "We've tossed around a whole bunch of names, like The Terminator, or something like that. And for various reasons "“ whether it wasn't a match, or we just couldn't come to terms with it "“ they didn't happen.

"We're always exploring a lot more than we actually end up doing. For instance: Michael Myers from the Halloween franchise. We talked about that at one point but it just never kind of panned out."
Contributed by KnowledgeBase
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In Mortal Kombat X, when Erron Black uses his X-Ray on Predator, his bullet will say "Ugly Mofo".

This is a reference to the popular line by Major Dutch Schaefer (played by Arnold Schwarzenegger in the first Predator film) where he refers to the Predator as "one ugly motherfucker" when he has his mask off.
Contributed by AkiraTheWarrior
During one of Cassie Cage's intros, Ultimate Mortal Kombat 3's arcade theme can be heard just as she takes her earbuds out.
In the intro to a Sub-Zero mirror match. Both Sub-Zeros will say, "You. You are not worthy of the name Sub-Zero. Who are you to judge?" A reference to a dialogue Noob Saibot and Sub-Zero said to each other in Spoiler:Cyber Sub-Zero's chapter in Mortal Kombat (2011).
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Originally Kano's "Cutthroat" variation was colored green, but this was changed to blue during development. The Green coloring was later used if Kano was selected without his variations.
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Selecting the Carl Weathers and Commando skins for Jax and Johnny Cage respectively will trigger a special animation on the preloading screen referencing a scene with Arnold Schwarzenegger and Carl Weathers from the original Predator film.
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When an X-Ray attack is successfully performed by Erron Black, he will shoot a bullet with his opponent's name on it.

Should his opponent be another Erron, the bullet will read "Me", and when performed against Predator, the bullet will read "Ugly Mofo", referencing a line from the original Predator movie.
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In Cassie Cage's Selfie Fatality, after she posts the picture she takes on a social network, the website contains a few references:

• The trending section has the headline "KILLING SPREE: Masked killer stalks campgrounds". This is a reference to Jason Voorhees from Friday the 13th, who is a downloadable character.
• An ad below the trending section has Johnny Cage starring in Ninja Mime. The movie was previously advertised in Mortal Kombat (2011), where ads of it are found in the Subway, Rooftop, and Street levels.
• The community list at the left lists all the organizations available in the Factions mode.
Contributed by Antwan
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One of Johnny Cage's Fatalities has him ripping open the chest of an opponent from behind them. The camera then moves to the character's front as Johnny looks through it stating, "Here's Johnny!" This is a reference to a famous scene from the 1980 film, "The Shining", in which Jack sticks his head through a hole he made in the bathroom door and exclaims the same phrase.
Contributed by Liraxus
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Johnny Cage and Goro's intro sequences against each other reference the "Mortal Kombat" movie, wherein they fought each other in Shang Tsung's tournament.

When Goro starts his dialogue first, Johnny will jokingly ask Goro about the "sunglasses" that Goro owes him, referencing the scene in the movie just before their fight in which Goro crushes Johnny's $500 sunglasses as an intimidation tactic.

Johnny's intro has him reference Goro "heading for a fall", referencing Goro's demise in the film.
Contributed by ProtoSnake
The mobile companion app for the game has several unlockable costumes that can be carried over to the main game itself upon being unlocked.

Among the many unlockable costumes in the mobile app is Scorpion's outfit from Injustice: Gods Among Us, as well as Jax's farmer outfit from Story mode and a classic costume for Kitana.
Contributed by MightyKombat
In one of Takeda's intros when facing off against Ermac, he will refer to him as "Error Macro." This is a reference to the rumour in Mortal Kombat 1 that Ermac was a secret character that could be unlocked due to a listing in the arcade machine's debug menu which read "Ermacs", referring to Error Macros.
While Mortal Kombat X is indeed the tenth main release in the franchise, the name is supposed to be pronounced as "X", not "10".
Contributed by Mass Distraction
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Moloch makes a cameo appearance in Mortal Kombat X during one of Quan Chi's intros, in which Quan Chi is holding Moloch's severed head.
Contributed by GhostLight