Monster Is a Mommy

Some kind of monster is terrorizing folks. After defeating or almost killing it, the cast follows the menace's trail back to its lair.

There it turns out the hostile critter has a very good reason for its actions, such as it was just protecting its cubs/litter. Extra points if they're cute.

Typically, the heroes inform the harassed populace about the creature's motivations, which may involve Shaming the Mob, and a suitable arrangement is arrived at to resolve the situation peacefully. Woe betide the townie or hero who took one of its litter as a Pet Baby Wild Animal, unless it's somehow become attached to them and convinces mommy to spare their life. Nursing a wounded fledgling back to health generally grants you a reprieve from momma's wrath, whether via karma, or because mom's smart enough to understand that you healed her child and grateful that you did. Sometimes the mom will be grateful enough to help out the person who helped her child(ren).

This trope can be expanded to cover any noble, maternal or protective behavior by an alien or monster that is misunderstood as predatory and/or aggressive.

There's also a fairly common inversion where the heroes battle one or more monsters before discovering the Hive Queen or Monster Progenitor, who is several steps up the Sorting Algorithm of Evil from her offspring—and is now out for revenge...

For highly dangerous human parents, see Mama Bear and Papa Wolf.

Examples of Monster Is a Mommy include:

Anime and Manga

Minor subversion in Saber Marionette J: We meet the cute cub first, then the scary parent.
In the anime Naruto a flashback to the character Haku's childhood shows him threatened by a stray dog for food. After he defeats it, you see the cubs growling at him, as it turned out it was trying to get food for its babies.
The chimera ants of Hunter X Hunter fit this trope in several ways. Most of them kill humans simply to feed and protect their Queen Mother, who in turn is doing it all for the wellbeing of her progeny. After the King is born, the more noble ants protect and nurture him in the same way, even organizing a sort of country-wide Battle Royale to find him worthy prey.
- Although it had nothing to do with the reason the lead character was tracking it down, he stumbles upon the ant he wanted to kill while it was busy treating the critical wounds of a 10 year old girl (accidentally injured by the protagonists) because she was important to the King (and the ant, by extension.) One of the characters notices that the ant acts just like a mother with her cub.
Diva from Blood+, although if you consider what she did to become pregnant...
The Detective Boys in Case Closed were imperiled by a monstrous bear when they went hiking in the mountains for mushrooms. (Turns out the bear was already quite pissed due to an overeager hunter who killed one of her cubs and hung its corpse in an attempt to lure her out in the open.)
Pretty much all the insects in Nausicaa of the Valley of the Wind, in the manga moreso than the film. They only attack Asbel because he crash-lands into a nest, and the scene in the well in a Dorok village, with Nausicaa petting a giant insect and leaving it under its eggs is quite touching. And not to forget that the Crypt of Shuwa is itself a mommy of sorts, containing in itself seeds for the post-purification world and a new race of humans.
The 13th Pokémon movie has a mother Zoroark and her child, a male Zorua.
In Heroic Age, the Iron Tribe's forces realize too late that the Bronze Race's (a race of giant space bugs that the Silver Tribe uses as mooks) homeworld is a lightly defended nursery planet. In other words, they carpet bombed alien babies.

Comic Books

This is one of three tests given to The Mighty Thor in the arc leading up to "The Reigning". He passes it handily, proving that he's not just Dumb Muscle.
During the Plunder Island arc in Thumble Theater, Popeye learns the gender of Alice the goon when, just as he's about to finish the fight, a smaller goon runs up and cries out, "Mama!"

Popeye: Mama?!

Films

Aliens: The theme of the film is mother vs. mother. (Ripley vs. the Alien Queen.)
Subverted in Dragonslayer: The dragon has a clutch of hatchlings, which are just as vile as the serpent that spawned them, and are accordingly slaughtered by the hero. And then It's Personal.
The Godzilla remake.
- There's also the original Japanese Godzilla who is a daddy (Though, Mrs. Godzilla is out there somewhere). Harming Godzilla's son is a VERY bad idea
Gorgo has fun playing with this one. Gorgo is captured and brought to London pretty early on, and then his mommy shows up, destroys London, rescues her baby, and the two of them swim away.
According to interviews, the Cloverfield monster is an infant who swam up to the surface and is terrified because he misses his mommy. If that sequel ever gets off the ground, she will definitely definitely appear.
The second Jurassic Park film has concerned mother AND father T-Rexes chasing our heroes all the way round the island, and then around San Diego, all because they have a baby T-Rex.
- In Jurassic Park III, the group is pursued and hunted by velociraptors as a member of the group has stolen two eggs from their nest. Upon returning the eggs and communicating with them via a replica velociraptor resonating chamber, the velociraptors leave without harming the group. The protagonist notes that dinosaurs are not monsters, but are sophisticated and intelligent animals. Man was the real monster, since the egg-thief wanted to sell the eggs for a million bucks.
In the mock documentary Dragon World, the frozen mummified dragon corpse the paleontologists have been studying is revealed three-quarters through to have been immature (despite the 20-foot wingspan), prompting the search for Mama Dragon's corpse (which is found and is the size of a small passenger aircraft).
Used to provide the sucker punch in the free (as in money and as in beer) movie Sintel by the Blender Foundation.
Sucker Punch: "Remember; don't wake the mother." They do.
In the beginning of the Douglas Fairbanks Sinbad the Sailor, Sinbad tells his audience of his encounter with the Roc, whose nest he invaded. He feared for his life against the giant bird, but "Wondrous, wondrous, this miracle of motherhood!" the Roc came only to warm her egg.
In Rise of the Planet of the Apes, Bright Eyes goes on a rampage when she's hauled from her pen against her will. Only after she's been shot and killed do her keepers realize she'd just given birth and was trying to get back to her newborn.

Literature

Inversion: The tale of Beowulf, in which the hero slays a very dangerous monster, and its even more dangerous Mommy goes on a Roaring Rampage of Revenge.
A different subversion seems in order in the short story "Honor is All"—set in the Dragonlance Role Playing Game Verse, it follows a noble knight who tracks and slays a dragon, and discovers that it has a hatchling. Just as he is about to do away with the infant dragon, however, he discovers that the creature he just killed was not a ferocious white dragon, but an albino silver dragon—one of the most powerful servants of Good, branded as a monster because of a tragic mutation.
In Stephen King's IT, the titular monster turns out to be a female, but that actually makes things worse rather than better.
Subverted in both the novel and film versions of Michael Crichton's The Lost World (one of the few plot points they have in common). The team takes an infant tyrannosaur back to the trailer to fix its broken leg; unfortunately, neither Mommy nor Daddy is very grateful for their saving the baby's life.
This was how I Am Legend ended: Turns out some of the vampires were trying to live their lives, and the last surviving human was the "real" monster.
The ending of Dav Pilkey's Dogzilla has the titular monster now accompanied with her puppies.
In Terry Goodkind's The Sword of Truth series, the hero makes an ally of an extremely dangerous dragon by helping her save her egg from the bad guy.
The old picture book Pickle Chiffon Pie involves three (naturally) princes sent on a quest. The geeky-but-nice prince nearly brings back a thoroughly unthreatening monster to make the titular pie for a king (It Makes (More) Sense In Context) until he noticed its children, which were even more Ugly Cute than the parent, peeking sadly from behind trees, whereupon he of course lets it go (and gets the king's daughter anyway). Causes some rather dramatic Fridge Logic - why didn't he just bring the kids too? - but still a good story.
In "Riki-Tiki-Tavi", the titular mongoose defends an Anglo-Indian family from a vicious cobra. Upon finding out that she had laid a clutch of eggs, he finds them, kills all the eggs but one, uses the last one to lure the cobra away from his owners and then kills the cobra and, ostensibly, the last egg.
Played straight in Reaper's Gale without the bonus points for cuteness. Onrack tracks an emlava, the story's equivalent of a steroid-using saber-tooth tiger, and kills it, only to realize after that its behavior was not typical of a hunting emlava. It had several cubs and his party takes over stewardship of them. Said cubs are less than cute, requiring the characters regularly check to ensure no limbs are in range of them.
Happens twice in Warrior Cats: once with a badger and her cubs trying to settle in ThunderClan territory, and once with a dead fox they found which happened to have a den full of cubs.
Brian Lumley applies this trope to some Eldritch Abominations in the short story "Concrete Surroundings".

Live-Action TV

Star Trek: The Original Series: The episode "The Devil in the Dark" uses this plot. While the Horta are neither cute nor cuddly (they look kind of like living lava flows, and the children are still unhatched eggs at the point of the episode), Spock's relaying of the mother/broodwatcher's emotions is one of the most powerful moments in Star Trek history and the civilized resolution to the conflict is one of the happiest ones.
- Similarly in the Star Trek: The Next Generation episode "Galaxy's Child," a huge interstellar alien attacks the ship. When the crew retaliate, accidentally killing the alien despite using minimal force, they discover that it attacked because it was pregnant. Then the baby (which they help deliver) gloms onto the ship and starts to nurse. Hilarity Ensues.
Also happens in the Farscape episode "Genesis" where the monster makes doppelgangers of the crew.
Inverted/parodied in the Amazing Stories episode "Mummy, Daddy", where an actor trapped in a highly-constricting mummy suit frantically attempts to reach the hospital where his wife is giving birth. His task is further complicated by 1. a hostile band of redneck hicks and 2. a real mummy.
Not quite a monster, but the weasel that infests the school and makes the janitor miserable in Ned's Declassified School Survival Guide turns out to be "a girl weasel!" and to have been looking for a nest all along. She is subsequently adopted with her young as secondary mascots.
The giant bug in the Sanctuary episode "Instinct".
Hercules: The Legendary Journeys approached this from a different angle. Herc goes about Greece slaying beasts and whatnot, and only after that he meets the Queen of Monsters, a gigantic several snake tentacled Lamia. Mind you later he finds the King of Monsters, who's just a giant played by Glenn Shadix who was trapped by Hera so that the Queen of Monsters would go evil and be willing to send her children after Herc. When they reunite the two ... erm... Squicky.
Parodied in Outnumbered; 6-year-old Karen invokes this trope to heap guilt on her mother for setting out a mouse-trap, arguing that the dead mouse was probably a mummy and all its babies will now starve.
Charmed has a variation in the episode 'Little Monsters', in that 'Monster is a Daddy', and is really a human who inadvertently disfigured himself while trying to use magic in order to make himself strong enough to take back his Half-Human Hybrid son from a group of maticores.
1970's Kolchak the Night Stalker episode "The Sentry". Kolchak investigates a rampaging monster in an underground facility. He discovers that during the drilling of a tunnel the creature's eggs were taken. When the creature gets its eggs back, it leaves peacefully.
Supernatural had Eve, the Mother of Monsters come back to Earth and freak major damage when Crowley and Castiel start kidnapping her children (ie monsters like vampires and werewolves) and torturing them for information.
Angel had "Fredless" where a giant bug demon was terrorizing the crew, and after Fred chopped off the head of another demon that had been attacking as well, it was discovered that the bug demon simply wanted its hatchlings, which had been inside the other demon's head.

Music

This trope is pretty much the whole point of the Voltaire song "Crusade", in which a dragon slayer makes the realization that the dragon he killed was a father.

Videogames

The Nue, the first major boss in Breath of Fire 3, is only attacking people to get food for its cubs (it's a really bad season). In an expansion on the trope, the cubs are all dead, but the Nue couldn't tell.
- Not so much that it couldn't tell rather than it was driven mad with grief and refused to accept that they were dead, to further emphasize the sadness that the vicious beast was really a grieving parent.
Chrono Cross actually uses this in a positive way: After having to kill a monster that's the Last of His Kind, they find that its last act was to give birth (hopefully to a self-sufficient brood), and continue the species. Oddly, you only discover this if you have a certain character in the party, and doing so deprives them of their Last-Disc Magic.
- Played for horror instead of sympathy in Chrono Trigger. Discovering that Lavos is sending its children out to consume even more worlds after consuming the protagonists' only underscores how urgently you need to kill them.
Final Fantasy VII allows you to examine a nest of chicks with treasure inside. Attempting to take the treasure forces you into an easy fight with the chicks' mother, after which you can steal it freely. However, even Cloud is guilty about doing it, and he becomes a lot less popular with his team-mates afterwards.
- Hacking into the relationship mechanics shows that this scene has no affect on anything driven by relationship points.
The Dynablade segment of Kirby Super Star uses this plot. Dynablade is attempting to gather food for her chicks, destroying crops in the process. After Kirby defeats her, he realizes the truth and helps feed the chicks by taking them to Whispy Woods, a boss that attacks by throwing an endless supply of apples at the player. Dynablade would later aid Kirby in the Revenge of Meta Knight segment.
The Movie Monster Game for the Commodore 64 has this as one of the objectives. As soon as the mommy finds the baby, the Instant Win Condition has the closing scene where everyone realizes the monster just wanted to recover the baby.
Early in disc 2 of Star Ocean the Second Story, the party has to hunt down and tame a Psynard to use as the Global Airship. When they discover it has young to care for, they decide to leave it be and find another way, but the Psynard, whom they saved just before this discovery, agrees to let them ride it around anyway. She just takes her kids with her.
Kat and Ana's chapter in Wario Ware: Smooth Moves basically plays this straight, where the giant rampaging oni was trying to get his son back.
A rather...uncommon example of this trope is in Parasite Eve, where Aya points her gun at Eve, then smiles and points it away once Eve points out she's pregnant. A twisted Eldritch Abomination-to-be with the game's Final Boss inside her, but still a mama.
In Tales of the Abyss, one of the first bosses you face is a Lyger, pretty much my favourite animal, who turns out to be female and protecting a clutch of eggs. Although the party still kills her, doing so is treated with some moral wieght, unlike the other monsters they cut down in spades, due to the Queen just trying to raise and feed her young.
In the second chapter of La Pucelle, you may end up killing the guardian of the forest. If you return there in the third chapter, Prier finds the monster's child, a cute bear cub, and chooses to take care of it to make amends. If she returns the cub to the forest, she'll gain a new spell.
At the end of the First Chapter of Mother 3 Flint goes to kill the Drago that killed Hinawa, only to be stopped at the last second by its baby.
The order is reversed in Call of Cthulhu (tabletop game):Dark Corners of the Earth, where after meeting the cute (if creepy) little girl, you meet her mother, a savage purebred Deep One locked in the attic, who proceeds to break out, maul you, and then kill the little girl.
In Final Fantasy Tactics A2, there is a quest sequence concerning endangered monster species. One of the missions has you protect an attacking Mamatrice and her chicks in a barfight from the corrupt bar-owner.
In Dragon Quest VIII, when you're helping Prince Charmless acquire an Argon Heart for his rite of passage, you eventually come across a Great Argon Lizard that's heavily implied to be the parent of all the regular Argon Lizards. Charmless, of course, orders you to slaughter it because he's not satisfied with the regular Argon Hearts you've found.
In EVO Search for Eden, the final boss of Chapter 4, the Yeti, turns out to have a wife (who tries to take her revenge) and a child (whose descendant tries to get even with you in Chapter 5).
The arcade game Savage Quest has a T-Rex mother whose clutch of eggs were stolen by a shaman (Karn) and his fellow cavepeople. An interesting twist is you play as the T-Rex and beat the living hell out of everything in your path to try to get those eggs back.
In Panzer Dragoon Orta, Orta battles what is known as an Els-Enora, a large flying creature. After defeating it, its young fly up to it, shrieking in what's most likely despair, and Orta immediately regrets what she has done. Then Abadd flies in and finishes off the mother, as well as murdering her children.
In one of Shara's later requests in Rune Factory 3, she takes an injured Wooly home with her. In the next request, you discover that the Wooly's mother is searching for her baby, and when Shara and baby run into Mommy, your character barely manages to avert an all-out brawl.
One of the minibosses of Kingdom of Loathing's Nemesis Quest is Argarggagarg the Dire Hellseal. After you beat him, you find out that he's actually female and has a child. Because of the general tone of the game, your character's response is roughly "Score! A new familiar!"
Why is Steelfeather, an unusually large and tough hippogryph, menacing the Alliance settlement of Fort Wildervar in WoW? Because the town is uncomfortably close to her nest.
Darkly subverted in Resident Evil 2. G, the constantly mutating creature that's chasing you, is revealed to be doing it because he's actually Mad Scientist William Birkin, and you are travelling with his daughter, Sherry. However, the only reason he wants her is because he needs a compatible host for the G-virus to reproduce, and Sherry is the only one available.
As a Brick Joke in the Portal 2 DLC, the bird that Atlas and P-Body fight lays three eggs. GLaDOS then 'adopts' them, to make them killing machines.
World of Warcraft: In the Howling Fjord quest, "We Call Him Steelfeather", the player has to discover why Steelfeather - a hippogriff - has become so ornery and aggressive towards the soldiers at Fort Wildervar. The player eventually discovers that the reason is a nest with hatchlings nearby. Obviously, Steelfeather is a female and a mother.

Web Art

In several of Fredrik K. T. Andersson's (often NSFW) artworks, a human adventurer is surprised to see the unholy child of some (still alive) creature. With the added twist that he's the father.
- Links here and here.

Webcomics

In The Inexplicable Adventures of Bob, Jean is kidnapped by Bigfeet because they think she knows the location of their missing child. Their hairless child is the strip's resident Gentle Giant, Rocko.
Inverted in Order of the Stick, when Vaarsuvius failed to consider that the dragon (s)he was killing might be a son. Several hundred comics later, his mom hunts him/her down...and she is pissed.
- And then the dragon targets Vaarsuvius's partner and children for revenge, and this trope is played horribly straight from the dragon's point of view. And all of its relatives.
Sluggy Freelance plays with this in the Non Sequitur Episode. A father bear takes his cub with him while roaming camp sites so people won't touch him believing he's a momma bear protecting her cub. Then Bun Bun takes the baby bear hostage (leaving it in the care of Kiki's chipmunks), to force the bear to rob a bank, with a teddy bear, to make the security guards think he's just a momma bear protecting her cub. Then he lets the baby bear go, just in time for the real momma bear to show up.

Western Animation

This also was the plot of one of The Herculoids' segments on Space Stars.
Played with in the "Woodland Critter Christmas" episode of South Park. Stan is enlisted by cute woodland creatures to kill a mountain lion that has been terrorising them, but once he has killed it he is dismayed to discover that it was the mother of several cubs. It then transpires that the cute woodland creatures are actually evil servants of Satan, and that the mountain lion was the only thing that could stop them.
- And further played with in the "Jewbilee" episode. A bear is seen dragging off several Squirts (Jewish Cub Scouts). The beast turns out to be a literal Mama Bear, who took the children back to her den for a birthday party for her cub.
In the Ben 10 episode "The Krakken", the monster was protecting its eggs. Milked a bit when, after the eggs are recovered, the hero prevents the monster from finishing off the poacher that had stolen them, and she relents and leaves peacefully.
- In an Alien Force episode, the monster mommy is BEN HIMSELF via a mix of his alien transformations with that species's asexual reproduction.
In Superfriends, Superman and Green Lantern are called to India to stop a rampaging elephant. After dealing with the damage it was causing, they decide to follow it and found that her calf is trapped in a hole and she cannot get her child out. Of course, doing that is a simple matter for two of the big guns of the Super Friends and the elephant immediately calms down.
In Avatar: The Last Airbender, Sokka adopts a cute little critter called "Foo Foo Cuddlypoops", who turns out to be a baby Saber-Toothed Mooselion. He is harmless - his mother isn't.
Played for ironic laughs in Buzz Lightyear of Star Command. An animal loving doctor saves the life of a young worm creature in front of its man-eating mother. Buzz expects that the mother will now be indebted to them and spare their lives. However, the worm does not share his point of view and still tries to eat the pair. Later, the doctor rebukes him for his way of thinking: "They still only see us as prey!".
In the second animated movie of The Land Before Time II: The Great Valley Adventure, the heroes (a bunch of young, talking herbivorous dinosaurs) discover an abandoned egg. They take care of it but what finally hatches out is a baby "sharptooth" (a tyrannosaurus rex). Sharpteeth have been antagonists since the first movie but they decide to keep him, call him Chomper and go on their merry way. (They become friends and chomper inadvertently saves their lives). But they end up getting pursued by not only one full-grown Sharptooth this time but two- you guessed it, the T-Rex mommy ( and a Papa Wolfish T-Rex daddy). But upon the returning of their baby, they end up not hurting the protagonists and actually rather saving them from "eggnappers", smaller, vicious egg-stealing dinosaurs.
There's a quick bit in Pocahontas where John Smith is about to shoot a huge, menacing bear. Pocahontas stops him, and the pair follow the bear at a discreet distance to a cave, where they see it is a mother with two cubs.
Brother Bear has this as a plot-twist late in the film.
How to Train Your Dragon has dragons continually raiding the Viking village of Berk, but Hiccup and Astrid discover that the dragons are trying to feed a huge Queen Dragon who otherwise would have eaten them. Thus in the climax, it is only when dragons and humans work together that they are able to end that threat and a new alliance of the species is born.
One episode of The Life and Times of Juniper Lee had a gigantic stone eating lizard rampaging around the park eating statues. After June tries to take it on and is beaten and knocked unconscious, the monster thinks she's the baby because earlier in the episode, June had gotten the baby's scent on herself. This resulted in the mother trying to feed June rocks that were chewed up in her mouth (similarly to a mother bird), and cleaning her by licking June with her massive purple tongue.
Filmation's Superboy did this twice in its first season.
- "The Deep Sea Dragon". A diver exploring a shipwreck finds a pearl in a chest. After he removes it and takes it to his ship on the surface, the ship is attacked by a seagoing dragon. It turns out that the dragon was genetically engineered, and she left her egg in the wreck for safe keeping.
- "Visitor From The Earth's Core". While Superboy and Krypto the Superdog are on an expedition to the Earth's core, Krypto finds a glowing black rock and Superboy takes it back to the surface to be analyzed. Later a giant crystalline snake comes out of the hole that Superboy dug and starts rampaging around. Krypto figures out that the rock is the creature's egg and alerts Superboy. They hatch the egg with their heat vision and return the baby creature to its mother.
An episode of The Powerpuff Girls had the main characters deal with a monster who was just looking for his pet kitty. Monster is a Pet Owner?
In Gandahar, a huge reptilian beast attacks the transport in which The Hero and his Love Interest are held captive, then proceeds to fuss over them as if they were her hatchlings.
The My Little Pony Friendship Is Magic episode "Boast Busters" inverts the trope: That big, scary star-bear was really just a very young cub in need of a bottle and a nap. We see Mama only in an Answer Cut; it's a good thing she didn't show up.
Possibly the case in a scene from the first season opening sequence of Rick and Morty, where a Cthulhu Expy is chasing a spaceship with Rick, Morty, and Summer, the obvious reason being that Summer is holding a baby Cthulhu. Sadly, there has yet to be an episode made to explain this scene.
In the Amphibia episode "Snow Day", the Giant Snow Weasel seems like the typical monstrous, bloodthirsty predator that menaces Anne and her friends every episode, until Anne finds its litter of cubs, whom it is trying to feed and protect.