El Ratoncito Pérez.

I went to the dentist today for maintenance treatment - scaling below the gum line (ouch!). In entering the surgery I noticed this tiny door, about 6” high, and asked the dentist, jokingly, “who lives in there then?” She said that’s for Perez. Apparently he’s a tooth mouse, like the UK tooth fairy, who leaves a gift in return for a tooth under a pillow at night. I asked if it was only for children, and she said yes, you can’t get anything for that wisdom tooth I took out. More info here :

The first appearance of Ratoncito Pérez came in a book of stories in 1877 by Fernán Caballero, the pen name of Spanish novelist Cecilia Böhl de Faber y Larrea, called Cuentos, oraciones, adivinanzas y refranes populares. In the book, there was a character called “la hormiguita”, meaning “a little ant”, who was married to Ratoncito Pérez, a gentle and timid mouse.

Years later, the Spanish author Luis Coloma, inspired by the the mouse character in Caballero’s book, would solidify Ratoncito Pérez in Spanish folklore by reinventing him as a Tooth Fairy. In 1894, Coloma was commissioned to write a story for the eight year-old King of Spain, Alfonso XIII, who had just lost his first tooth. In Coloma’s story of Ratoncito Pérez, the mouse lived with his family in a cookie box on the streets of Madrid. Ratoncito Pérez would travel through the pipes in the city to reach the young children of Madrid who had lost their teeth.
The story was a hit and Madrid even paid tribute to the story of Ratoncito Pérez by placing a plaque where he was supposed to have lived in the story, reading: “Here lived, in a box of cookies, Ratoncito Pérez, according to the story that the father Coloma wrote for the young King Alfonso XIII.” The original manuscript of the story is in the vault of the Royal Palace Library.