Hanako-san or Toire no Hanako-san (Hanako of the toilet) is a Japanese urban legend

Japanese urban legends

Japanese urban legends are enduring modern folktales of paranormal creatures and their attacks on innocent victims. They rarely include the fantastical or animistic yokai of earlier Japanese superstition, and are mostly based on onryo, Japanese ghosts who have become vengeful spirits and take...

 about a young girl who haunts school bathrooms. She will appear if you shout her name.

Legend

If you go to the last stall in the girls bathroom and knock three times before asking 'Are you there, Hanako-san", a voice will answer "I'm here". If you enter the stall you'll find a small girl in a red skirt, waiting for you.

Hanako-san is a popular and widespread urban legend, often played by school children as a right of courage, or a method of hazing for new students, similar to the Bloody Mary

Bloody Mary (folklore)

Bloody Mary is a ghost or witch featured in English folklore. She is said to appear in a mirror when her name is called three times or sometimes more while in a dark room, depending upon the version of the story, often as part of a game or dare.-Overview:...

 urban legend in Western schools.

Variations

Hanako-san has been noted to have various origins and behaviors, depending on the area or school, and is a widespread legend across Japan. Her appearance can also be different, but is usually that of a young girl with bobbed hair and a red skirt. She can be either mischievous, malevolent or benign.

Yamagata prefecture: After Hanako-san has answered and you enter the stall, you'll find a three headed lizard who had mimicked a girl's voice; it will then eat you.

Iwate prefecture: After you have called Hanako-san, a large white hand emerges from the door.

Kanagawa: After you have called her, a blood stained hand will appear.

'Hanako' was a common and typical girl's name in the Japanese 1950s when the legend supposedly began.

Manga

• Hanako-san is one of the main characters in the manga Hanako-san and the Terror of Allegory.
• Higanbana no Saku Yoru ni
  Higanbana no Saku Yoru ni
  , subtitled The Unforgiving Flowers Blossom in the Dead of Night, is a Japanese manga written by Ryukishi07 of 07th Expansion and illustrated by Ichirō Tsunohazu. It began serialization in the May 2010 issue of Fujimi Shobo's Monthly Dragon Age magazine...
  
  is a story that creates a legend similar to this one.