A classic folktale.
Once Upon a Time, there was a little girl called Goldilocks, so-named for her blonde hair. One day, she took a walk in the woods and came to a house where three bears lived - a papa bear, a mama bear and a baby bear. The bears weren't home, but they'd left their door unlocked, so Goldilocks came in.
She found three bowls of porridge in the kitchen. Being hungry, she tasted them: Papa Bear's was too hot, Mama Bear's was too cold, but Baby Bear's was just right, so she ate it. Then there were three chairs she tested. Papa Bear's was too hard, Mama Bear's was too soft, but Baby Bear's was just right — or it was until she sat on it and it broke.
Then there were the bears' three beds. Papa Bear's was too hard, Mama Bear's was too soft, but Baby Bear's was just right, and she climbed in and fell fast asleep.
Then the bears came home. They found evidence that someone had entered their house, eaten their food, used their furniture, etc. When they discovered the culprit, still sleeping in Baby Bear's bed, you can guess how it ended.
Like many Fairy Tales, this one has evolved over the years. According to that other wiki, the original tale was probably that of Scrapefoot the vixen (as in a fox), who was an unwelcome guest at the bears' castle (yes, you read right. Castle). Robert Southey apparently heard this tale from an uncle and in 1837 became the first to publish it. However, he accidentally thought it was the wrong kind of vixen, which got her changed into a mean old woman who, after not being invited around to the bears' place, decides to go check it out for herself. She falls out the window and is never seen again. Goldilocks as we know her only turned up in Joseph Cundall's version 12 years later, and only to stop confusion with other old ladies in other fairy tales. Nor was she the only little girl; for a long time, she was dubbed Silverhair (and George MacDonald did a Shout-Out to the tale in The Golden Key by that title).
Full text here, with a link to many variants of it.
As with other fairy tales, we have seen Goldie and the bears get fractured until they are shattered. Notable adaptations include Bugs Bunny and the Three Bears and the Terrytoons version, the latter of which is notable for making the bears Italian, replacing the porridge with spaghetti, and giving us "SOMEBODY TOUCHA MY SPAGHETT!". We've also seen her get added to the lineup of the Dark Parables, which makes her not only an adult, but an Action Girl, and a supporting villain in Fables where she's a terrorist for hire.note There's also Goldie & Bear, which takes place after the story, and depicts them as friends. The characters were used in the movie Puss in Boots: The Last Wish, where the Bears are a loving crime family, and adopted Goldilocks into their own as she was an orphan. She acts as the brains of the crime outfit, and Mama and Papa Bear refer to her as their daughter.
This story provides examples of:
- Adaptational Heroism: In Eleanor Mure's version of the story, Goldilocks was an unnamed older woman who broke into the house out of spite, since they refused to let her in. When the bears caught her, they punished her by trying to burn and drown her. When it didn't work, they impaled her on a steeple. In Southey's version, however, Goldilocks had no clear motive. Later versions of the story have Goldilocks being a naive child who didn't know what she was getting herself into, causing the bears to either scare her off or befriend her.
- Adaptational Villainy: The bears are often depicted as the villains, despite being heroes in the older versions. They are typically depicted as bears who maul an idiotic child to death for breaking into their home. Other Versions have Goldilocks being saved from the bears.
- An Aesop: Respect the property of others, and don't take or use their stuff without their permission. Especially if they're bears.
- Age Lift: The original story features the intruder as an old lady, while the modern mainstream version depicts her as a little girl.
- Bears Are Bad News: The bears tend to be portrayed as quite nice, but Goldilocks usually ends up regretting incurring their wrath: depending on the version, she either gets killed, or is simply given the fright of her life and chased out.
- Beary Friendly: The bears are frequently shown as a quiet and pleasant little family, just understandably annoyed at Goldilocks for messing with their things.
- Bowdlerise: In more recent tellings of the story, especially for children, the bears either scare Goldilocks away or make her apologize for using their things without permission. In earlier versions of the story, they were … not so nice.
- Bullying a Dragon: Mure's version of the story has the woman already aware that the homeowners were bears. Rather than, accidentally finding a house without anybody there and not knowing who the occupants were.
- Catchphrase: Baby Bear: "My X is just right!" Goldilocks uses the similar "This X is just right!”
- Character Name and the Noun Phrase: Goldilocks and the Three Bears.
- Death by Adaptation: Some versions end with the bears eating Goldilocks.
- Exit, Pursued by a Bear: In the end, Goldilocks gets chased off by three hungry, pissed-off bears. Sometimes, this ends in death, sometimes she manages to get away.
- Fractured Fairy Tale: Many, but arguably the two best known are from Fables and Roald Dahl's Revolting Rhymes. And Goldie & Bear is an entire animated Disney series featuring Goldilocks (Goldie) and Baby Bear (now just Bear) as the main characters.
- Funny Animals: The Bears live in a house, sit in chairs, sleep in beds, and eat porridge!
- Hero Antagonist: The three bears in multiple versions, as well as multiple adaptions, oppose Goldilocks, sometimes to the point of killing her, but they're understandably just trying to protect their stuff. In the older versions, they were very good-natured and heroic.
- Idiot Hero: In the earlier versions, Goldilocks deliberately broke into the house out of spite, despite knowing the homeowners were a trio of bears. In recent versions, Goldilocks was reimagined as a child who entered a (seemingly) abandoned home in the woods and simply didn't know the owners were bears. Still, it's not the best idea to do what she did.
- Meaningful Name: Goldilocks has locks of golden hair (or, in older variants, Silverhair). Not to mention Mama Bear, Papa Bear, and Baby Bear.
- Nuclear Family: Mama, Papa, and Baby Bear, who live in a nice little house in the forest.
- Painting the Medium: Robert Southey's version represented the three bears' voices with different fonts and text sizes. Many later adaptations have followed suit.
- Rule of Three: Three bears, three bowls of porridge, three chairs, three beds.
- Schmuck Banquet: Three bowls of freshly-cooked porridge just sitting there unattended? Eh, what could go wrong? (An Unbuilt Trope in this story, because the meal wasn't specifically set there to lure passing humans; Goldilocks was just greedy.) In one Bugs Bunny story, the bears did intend to lure someone. Bugs becomes their victim because Mama Bear made carrot soup instead of porridge.
- Sleeping Single: Implied — how else could Papa Bear's bed be too hard, but Mama Bear's too soft? (Of course, nowadays, there are beds with adjustable hardnesses on each side, but still.) It should be noted that in the earliest versions of the story, the bears were not identified as a family unit, so them all sleeping in different beds made more sense. The relations between the three bears is still ambiguous in some languages where they are only known by their sizes, such as the little bear, the middle bear and the big bear.
- Snooping Little Kid: Goldilocks. In some versions, this is accentuated by Goldilocks looking in through the window and peeping through the keyhole, before entering the bears' house.
- Super Window Jump: How Goldilocks makes her escape, in most tellings.
- Swiss-Cheese Security: Goldilocks has no difficulty getting into the bears' house. In most tellings the bears leave the door open while they go out.
- Too Dumb to Live: Hey, look, a mysterious unlocked house in the middle of the creepy woods. Let's go inside!
- Vegetarian Carnivore: The bears are introduced cooking a meal of porridge. Technically, bears are omnivorous, but literary scholars have pointed out the vegetarian meal serves the narrative function of helping young readers feel less worried that the bears will eat Goldilocks.
- Villain Has a Point: In the stories where they're supposed to be the bad guys, you can't really blame the bears for what they do to the protagonist. She invaded their home, broke their stuff, ate their food, and stole one of their beds.
- Villain Protagonist: Usually downplayed. Goldilocks is a home intruder who spends most of the story actively committing unlawful entry, theft, and vandalism of private property, but depending on the version, it could be down to naïveté or childish naughtiness rather than true maliciousness. In the earliest versions, she was a mean lady who did everything out of spite.