Glass Slipper

The Glass Slipper is a fictional shoe belonging to Cinderella, first used in the 1950 film of the same name. It was created through the use of magic by her Fairy Godmother in order for her to attend the royal ball. It also plays a somewhat-significant role in the film's third sequel Cinderella III: A Twist in Time. It was known as Cinderella's trademark object. It is also the only object to find the princess, which is Cinderella and Anastasia (formerly) at the third sequel due to magic by her evil stepmother.

Cinderella
The glass slippers are the dainty footwear conjured up for Cinderella by her Fairy Godmother (as well as an additional accessory to her well-suited ballgown) so she can attend the ball at the King's castle, despite not having anything suitable to wear. The slippers remain on her feet as she dances with Prince Charming. As she flees the castle when the clock strikes midnight, she loses one of them on the steps as she leaves. When the spell lifts, the slipper remains intact, as does the one that is still on Cinderella's foot. The Grand Duke picks it up and searches through the kingdom to find the young maiden whose foot fits it, for the one who does will become the Prince's bride.

After searching the whole kingdom, the Grand Duke comes to Cinderella's home. Anastasia and Drizella both try to force their feet into it, with Anastasia even putting on an act that she remembered dancing with the Prince, but fail in doing so. Cinderella comes down from her room and asks if she can try it on. Lady Tremaine insists Cinderella is only the maid, but the Duke says that his orders were every maiden. As the Duke's Herald delivers it to her, Lady Tremaine uses her cane to trip him, causing the slipper to fly out of the Herald's hands and shatter into pieces upon hitting the floor. Cinderella surprises everyone by revealing that she has the other one. When it fits her foot, she is taken to the castle to be married to the Prince. The slippers are seen one last time on her feet during the wedding.

Cinderella III: A Twist in Time
In this film, Lady Tremaine takes the Fairy Godmother's wand and turns back time so the Prince will marry Anastasia. When the Grand Duke comes to their home, she makes the slipper a bigger size so it can fit Anastasia's foot. As they leave to go to the palace, Cinderella comes downstairs with the other one. Lady Tremaine breaks it and threatens her. Anastasia wears the other one throughout the rest of the film.

House of Mouse
The glass slippers are Cinderella's signature clothing in the series, along with her ballgown.

In the pilot episode, after Donald Duck took over as the host of House of Mouse, Cinderella and the other guests fled away from the bad show. In that process she left behind one of them.

In the second episode, when the Big Bad Wolf blows his trumpet on stage during the Big Bad Wolf Daddy musical number, various fragile objects break, from the chambers of the Enchanted Rose to the glass slippers.

In the episode "Where's Minnie?", they are listed as one of the "Scuttle's Lost & Found" objects.

In the episode "Ask Von Drake", the Grand Duke tried to fit them on Anastasia's foot, until Ludwig von Drake advises him to try them on Cinderella.

Once Upon a Time
The glass slippers appear in Once Upon a Time, though, rather than the Fairy Godmother giving it to Ella, it's Rumplestiltskin.

Twice Charmed
The glass slippers appear in the spin-off musical. In this version, the Tremaine's Wicked God Father turns back time, and they are given the chance to break both of them. They do so that the prince can never identify Cinderella.

Trivia

 * In reality, glass footwear would be quite uncomfortable to wear, much less to walk or run in cause there's no cushion for the soul of the foot. However, Cinderella does this quite comfortably, likely because of them being imbued with magic. Coincidentally, in the 2015 film, the Fairy Godmother remarks that they are really comfortable.
 * Cinderella leaving behind one of the slippers on the castle stairs while running away from the ball is the second of three times she has dropped her footwear in the original film.
 * In reality, there would be a constant sound coming from any form of glass footwear as it is pressed against a solid surface, such as a ballroom floor or pavement. In Cinderella's case, this sound is non-existent. However, in Cinderella III, when it is made by Lady Tremaine to fit Anastasia's foot through the use of magic, a noticeable clanking noise is heard when she walks and when she dances with the prince. This may be because it was not meant for her, but for Cinderella.
 * In Cinderella III: A Twist in Time, it is stated by the king that the slipper is a women's size 4½.
 * For some reason, the slippers do not revert when the magic wears off, like the ballgown does when the clock strikes midnight, which suggests that they were actual glass ones. Cinderella thanks her Fairy Godmother for letting her keep them.
 * In the live-action film, it's heavily implied that the reason the glass slippers didn't disappear was because they were pure magic and did not derive from an already existing object. Instead of transforming Ella's current shoes, her Fairy Godmother asked her to remove them and she conjured up the glass slippers onto her feet.
 * Kevin Jonas, who is part of the Jonas Brothers, gave his wife, Danielle, real glass slippers as a wedding gift on their wedding day in December 2009.
 * When Cinderella is shown in the Disney Princess franchise, the slippers are more bluish than the type of transparent glass.
 * When Cinderella dropped one of the slippers on the stairs, she doesn't limp on one leg. In reality, a person wearing high heels would.
 * The slippers have hearts at the front in the animated film. In the live-action film, they are replaced with golden butterflies.
 * In the animated film, Cinderella loses her left slipper. In the live-action film, she loses her right slipper. Also in the animated film, it's the slipper that Cinderella left at the ball that got shattered while in the live-action film, it's the one that Cinderella brought home that Lady Tremaine shattered.
 * In the 2015 live-action film, the slippers were made from Swarovski crystal in 3 separate parts (toe box with the butterfly, vamp & heel) joined together, because costume designer Sandy Powell later found out that glass doesn't sparkle, and they wanted the slippers to sparkle.
 * Lily James never wore the slippers. In an interview, she said that the slippers didn't fit her and were uncomfortable. Instead, she wore leather shoes through the entirety of the ball and CG was used instead to mock up the appearance of the slippers.
 * Many people believed that the Perrault's version of Cinderella was mistranslated into English regarding the glass slipper. They believed that the word vair(fur) from the glass slipper was misread as the homophonous verre (glass).
 * In the Chinese version of the story, the slippers are made of gold and were wished up from the four parts of the bones of a fish Ye Xian (Chinese Cinderella)'s befriended (which was 10-foot long and had golden eyes & scales; versions varying as a guardian spirit sent by her dead birth mother to her mother's reincarnation), which she was ordered to bury at the corners of her bed.
 * Even her silk gown & her cloak of kingfisher feathers were from the same wish.
 * The slippers' size was reputedly tiny, an evidence of the Chinese fascination for small feet (leading to the practice of foot-binding). Whichever maiden not its owner tried to wear it, it magically shrunk in size.