One Bad Mother

Have you noticed that the word "mother" is a common villain name? Maybe it's ironic, maybe it's symbolic, maybe it overlaps with the Hive Queen, but writers seem to think it's a scary word. And sometimes, of course, it's a Curse Cut Short that's very effective at Getting Crap Past the Radar.

This can also be known as:
 * An Evil Matriarch of some sort (similar to "queen")
 * A twisted version of a "mother" (spreading The Virus and considering the victims her "children", for example)

See also Almighty Mom, Monster Is a Mommy, Mother of a Thousand Young.

Has nothing to do with Abusive Parents. Usually.

Anime and Manga

 * The Un-Mother on Inuyasha.
 * Durarara!! has

Board Games

 * The Mother in Risk 2210 is a supercomputer that nukes entire continents. Not a villain, but very scary.

Comic Books

 * A variation: Granny Goodness from The DCU.

Film

 * The ship computer in Alien was MU-THR 182 or something like that. And it wasn't the villain, nah, it was just programmed by the Weyland-Yutani Company (who we all know are eeeeeevil). If anything, Ash turned out to be a sort of villain.
 * Pretty sure the titular Alien was the villain. Ash was just a tool. And "Mother" was just prioritizing the mission goal over the crews' lives.
 * The 4th movie, Resurrection, was set much later and "Mother" has been replaced with a new OS, "Father". This trope is played with when someone takes over the computer and a female voice announces to the evil scientist "Father's dead, asshole."
 * Mother from Psycho - if not the trope maker, then definitely a popularizer.
 * Animal Mother from Full Metal Jacket is (presumably) an example of the Curse Cut Short version.
 * Mother Gothel from Tangled.
 * Averted in Sneakers—Dan Aykroyd's character was named "Mother", but was a good guy.

Literature

 * There's the musclebound female Marine codenamed 'Mother' in Matthew Reilly novels. A hint, it's not because she's a maternal figure... though she is one anyway.
 * Another "ship's computer" in Remnants. She's sentient, not really evil but unfortunately, sort of insane. The series also features the "Children," an alien species who worships her as their god.
 * Interestingly, one of the Animorphs spinoffs had had an intermediate villain named "Father."
 * The Other Mother.
 * The Anita Blake series has an ubervampire called "Mother Gentile".

Live-Action TV

 * Pushing Daisies has the Norwegians' high-tech van thing called Mother. They're not villainous per se, but are definitely antagonistic.
 * Shelly Winters played the villain "Ma Parker" on the 1960s Batman series.
 * Who was based on the real life Ma Barker who Winters would also play in a movie.
 * In the Lost episode "Across the Sea," we meet the island's previous protector, known only as Mother. As the writers acknowledge, her bad parenting 2,000 years before the events of the series has led to pretty much everything bad that ever happened on the island.
 * The Mother of All
 * One episode of Doctor Who had three evil alien witches called Carrionites, of which the older two were both called "Mother" by the third.
 * There was also the Family of Blood, of which one member was called Mother of Mine by her two children.

Music

 * There is a song by Danzig called "Mother".
 * Pink Floyd also did a song about "Mother". Shudder.
 * "Ma Baker" by Boney M, which was based on Ma Barker, though it played up the fictional accounts that she was the ringleader of the Barker-Karpis gang.

Tabletop Games

 * The Qedeshah, a bloodline of vampires from Vampire: The Requiem, is imbued with a strong mothering instinct. Members of the bloodline with high Humanity and willpower tend to be kind and caring, but as one of these slides down the Humanity scale, they start to resemble this trope more and more. It doesn't help that they have trouble siring their own childer, with all male versions dying in a very unpleasant manner. And you had better hope you don't hurt one of their "children"...

Video Games

 * Mother Brain in Metroid.
 * Mother Brain in Chrono Trigger. Not quite certain why it shares a name with the Metroid example.
 * Mother Brain from Phantasy Star II. Really, that name is almost a trope in itself...
 * The Mother in Prey.
 * Mother of Wild ARMs is the Big Bad and Omnicidal Maniac leader of the demons.
 * Mother in La-Mulana. Justified as she actually is a creator goddess.
 * In World of Warcraft, there are several examples of this, such as the Den Mother and Mother Shariz
 * The plant-like entity called Mother by the children in Sanitarium.
 * Mass Effect's Matriarch Benezia qualifies, not just because of her title but also because she was the literal mother of one of the main characters (although to be fair it was more a case of.
 * Mother Slime in Kingdom of Loathing.
 * Mother hellseals, too.
 * Mother from Siren 2, the creator of the various body-snatching avatars. If she has a real name, we never find it out.
 * Galerians has the supercomputer Dorothy, who is referred to as Mother by her children.
 * In Dragon Age, you have the extravaganza that is the broodmother. In Awakening
 * Elizabeth Greene in Prototype has the in-game codename of "MOTHER".
 * All of the ruling demons in the latter half of Shin Megami Tensei: Strange Journey are "Mother"-type demons, based on over-arching entities like Tiamat and Ouroboros. The final demon is "Mem Aleph," the mother of thought and the "memory of the earth."
 * Mother is incredibly displeased that you have not mentioned her! Those dogs in The Resistance and the so-called City of Heroes might call her Mother Mayhem, but you know that Mother LOVES you, don't you? DON'T YOU? Of course you do. Because Mother loves you too...
 * Mother from D2, a supercomputer that resembles a giant silver pregnant woman seen crotch-first (complete with legs in stirrups).
 * Mom from The Binding of Isaac, commanded by her Lord to offer Isaac as a sacrifice. She is the Final Boss.
 * Psychonauts has a variant with the Den Mother, the boss of the Milkman Conspiracy.

Web Original

 * Elizabeth Avery from Lonelygirl15 is usually referred to as simply "Bree's Mom".
 * The SCP Foundation: SCP-597, referred to as "The Mother" by those it enslaves—well, at first, anyway.
 * A Very Potter Sequel has Umbridge commonly refer to herself as "Momma" since she wants to view the students as her children. The fact that she believes in the toughest of tough love and is Ax Crazy to boot makes this a very bad thing.

Western Animation

 * Mom in Futurama
 * Mother Mae-Eye from the Teen Titans animated series.
 * M.U.T.H.E.R., the crazy EarthBound-style master-computer in the bunker from The Venture Brothers
 * Ma Beagle from DuckTales (1987).
 * The witch from "Rapunzel" is traditionally named Mother Gothel. In Tangled, she's a My Beloved Smother who psychologically manipulates her daughter into staying with her for life so that her source of immortality (Rapunzel's hair) will always be close.
 * Ma Mayhem from the "Eggbaby" episode of Batman Beyond.

Real Life

 * Maurice "Mom" Boucher of the Hell's Angels. Yes, he's a man, but making fun of gangsters for their name is usually not a good idea.