The phenomenon in B Movies from the 1950s to early 1960s in which rampaging monsters/serial killers seem to focus their "random" attacks mostly on women. Usually young, innocent, vulnerable women. Although such films may show a man or two as victims, the real focus is on the ladies. For instance, if the movie includes a montage of attacks, expect every victim shown to be female.
This seems to be a wide-scale application of the Disposable Woman concept, sans any significant connection to The Hero; further, the deaths carry no more than the normal dramatic weight, and do not motivate the Hero to action any more than would male deaths. All other things being more or less equal, the director will simply choose to populate his movie with female victims. And then, of course, there are plots in which the killer will specifically target females.
One would assume, in this age of equal rights and feminism and all, that this would be a Discredited Trope or even a Dead Horse Trope. But no, the trope is alive and well. Apparently, the sight of women being terrorized on screen is just more... um... titillating. Or a good way to show just how evil your monster is by attacking poor defenseless girls. Also don't forget that Girls Are Really Scared of Horror Movies. Either that, or it's because this trope is based on reality — real-life serial killers target women much more often than men. Ted Bundy, Ed Kemper, Gary Ridgway, and even Jack the Ripper killed women exclusively, or nearly so.
As a direct result of this trope, many slasher movies have a Final Girl (and one with no form of self-defense training at that), since audiences are somehow more likely to root for a young, nubile, defenseless (white) woman on the run from a psychopath who gutted her friends like fish, as opposed to a man in a similar position.
If the women are abducted rather than killed, it's probably because Mars Needs Women. See also Distressed Damsel, Monogender Monsters, Touch of the Monster. Many this trope's aversions come from the fact that Men Are the Expendable Gender.
In Ranma ½, the monstrous eight-headed Yamata-no-Orochi is an enormous pervert who likes to see women's underwear, naked women, and women in general. It also loves eating them. It even has taste buds for it. Men? They just taste bitter, they piss it off, and it kills them on sight. This is roughly based on the myth of the Yamata-no-Orochi, which demanded maiden sacrifices.
A Justified Trope in Witchblade. The I-Weapons usually go after women; women who just happen to have the Cloneblades of the Witchblade they are attracted to.
In Bleach, Ichigo is confronted by a Hollow named Grand Fisher, named for the hook on his head which he can give the appearance of a small child to lure his victims, with Rukia explaining that his favourite prey are women. He is also the hollow that killed Ichigo's mother
In the first OAV of Vampire Princess Miyu, all of the Shinma of the week's victims were female: two schoolgirls, a college student, an Office Lady and a House Wife. (And we actually witness the poor House Wife's death; she's picking some silks in a store, the glass of the window suddenly cracks a little, and all of a sudden we see her dead on the floor.) Somewhat justified in that Aiko, the girl "commanding" the Shinma, had her life "ended", therefore the Shinma believed it had to finish other female's lives as well since they had the lives that poor Aiko couldn't aspire to anymore.
Also, more than one Shinma from the TV series and the manga preyed more on women than on men, or only on women. See the Mad Artist Roh-Sa, to start, who captured vain and pretty women via the promise of making their beauty last forever. Literally.
A staple of HorrorHentai...especially that which involves tentacles.
While men and women both die plentifully in works by Frank Miller, the fetishistic way that women are killed, often while they're partially or completely naked, has led to accusations of Author Appeal. As an example, Sin City's male villains in particular are nearly always some form of misogynistic scum bastard who murders and/or does truly awful things to women and girls, to the point where in A Dame to Kill For, the second major Sin City story, Ava, the titular Femme Fatale, plays on Dwight's violent protectiveness toward women by casting her perfectly innocent husband, Damien Lord, as one of these in her Wounded Gazelle Gambit.
Semi-subverted in The Descent. Despite being the second and third to go, the females manage to determine its weakness, then subsequently deal the most damage. They were extreme sports nuts, while the men are standard cannon fodder explorers.
In the Dean Koontz novel, Shadowfires, a Mad Scientist-turned-monster stalks his ex-wife out of (at first) murderous intentions. But after slowly becoming more animalistic, and raping and killing and eating an innocent bystander, his desires towards his ex-wife turn more amorous and cannibalistic.
Koontz does this a lot. Dark Rivers of the Heart was a particularly graphic example.
In the Hannibal Lecter series, all non-Lecter killers (Jacob Garrett Hobbes, Frances Dolarhyde, and Jame Gumb) specifically targeted women - Dolarhyde killed whole families, but it was the mothers that interested him. Lecter himself was far too much of a Magnificent Bastard to particularly care whom he killed, and it's implied that he had a fairly even split in terms of victims.
Dracula: the title monster feeds on men to survive, but the only new vampires he creates are women. Many critics note the sexualized nature of the violence between men and women throughout the story, with blood-sucking and stalking being seen as metaphors for sex.
Played straight with the Hunter in the Coldfire Trilogy, but justified- he's made a study of human behavior and decided that targeting women is the most effective way to terrorize a society, and since he feeds on fear...
The Horror of Party Beach includes two male victims alongside its twenty-four girl deaths. And that figure doesn't take into account the film's Female Victim Montage. Adding to the misogyny count, many of those victims were holding a slumber party at the time. Cue "panty raid" jokes.
Mike: Do you think most guys who make movies have issues with women?
Horrors of Spider Island, in which the entire victim pool is female. Except for one lecherous guy near the end. As the commentary said: "I wonder how this movie really feels about women."
On the one hand, this is somewhat justified as the plot is a Closed Circle (a troupe of dancers survived a plane crash and ended up on a desert island; their manager, the only man around, got turned into the monster). On the other, it also spends a lot of time focusing on scantily-clad and/or (supposedly) naked women doing things like swimming, dancing, and fighting one another. And supposedly the original German version was more explicit.
In the Star Trek episode in which Jack the Ripper turns out to be an evil alien entity, Spock says it focuses its attacks on women because "women are more easily and more deeply terrified, generating more sheer horror than the male of the species." Though the dialogue doesn't have this caveat (and hence lacks this implication), that actually makes sense in the context of Victorian England, where women were supposed to be delicate and helpless and this attitude was encouraged in them.
On The League of Gentlemen, the demonic blackface minstrel Papa Lazarou goes after women to make into his "wives". In a bit of a twist, though, all of the women are over 50, and he's just as dangerous towards men if they come across his path. Also, due to the format of the show, almost all the women are played by men in drag.
The titular serial killer in Dexter is not an example, but many of his victims are. The Ice Truck Killer targets only women, and in particular prostitutes. This is similar to real serial killers, who (being primarily men) will target prostitutes under either some misguided "morals" that they have, or simply because they feel they won't really be missed.
Inversion: Zoo Tycoon 2 has a dinosaur expansion, and the dinosaurs are the only animals that will attack guests. The only guests they'll harm, however, are adult males.
The monsters in the Torna Canal section of Final Fantasy V only target females. If you pay attention, their attacks hint at The Reveal of Faris' gender in the next chapter.
The Orthros in Final Fantasy XII will only appear if your party consists of Fran, Ashe, and Penelo - all of whom are female. Granted, it will still attack male characters if they are switched out, but the monster seems to prefer attacking females.
Pyramid Head. He is, among other things, a representation of the main character's masculinity issues, and is only seen to harm a single creature (excluding the protagonist) that isn't obviously female.
Justified in Dragon Age; the darkspawn reproduce by abducting humanoid women, gang-raping them and force-feeding them darkspawn flesh and their own relatives, and gradually transforming them into Broodmothers - towering, multi-breasted, betentacled horrors with nightmare faces who give birth to thousands more darkspawn.
Following the Real Life examples below, Wrecking Paul from Everyday Heroes is a serial killer who targets women. Including, if no one else is available, his own partners.
Shredded Moose was particularly horrible about this - Brew, the "hero", killed or abused women as a matter of fact; we were supposed to laugh at and approve his acts.
Neopets once had something called the "Terror Mountain Ski Lodge", where members of the staff were picked off by the Ski Lodge Killer. The first victim was a male, but then the killer killed 8 female staff members in a row. Eventually the killer went back to male victims (as there were only two women left).
The SCP Foundation has SCP-847. Usually a normal seeming (if damaged) female mannequin, it comes to life if a woman approaches within 100 meters of it, with a single minded determination to murder the woman and [DATA EXPUNGED]. It's only known weakness is electricity, which will temporarily render it dormant.