Mermish Song

A Mermish song is a form of communication and an art form unique to Merpeople. Sung in the Mermish language, its most notable characteristic is a powerful enchantment that dictates how it is perceived both above and below water. It is created and performed by the Merpeople community, such as the colony residing in the Great Lake at Hogwarts School of Witchcraft and Wizardry.

The primary magical property of a Mermish song lies in its medium-dependent intelligibility. The experience of hearing the song differs drastically based on the listener's environment.

• Above Water: When heard above the surface, the song is completely incomprehensible to human ears. It is described as a high-pitched, eerie, and unpleasant shrieking or screaming noise, devoid of any discernible words or melody. This was the sound that emanated from the Golden Egg when opened in the open air.
• Below Water: When the listener is fully submerged in water, the shrieking noise transforms into a clear, albeit eerie, song. The lyrics become perfectly understandable, allowing the singers' message to be conveyed. This magical property served as the core of the puzzle for the Second Task of the Triwizard Tournament.

The only detailed instance of a Mermish song in the series occurs during the 1994-1995 Triwizard Tournament, where it was used as the clue for the Second Task.

• The Golden Egg Clue: The song was enchanted within the Golden Egg awarded to each of the four Triwizard Champions—Harry Potter, Cedric Diggory, Fleur Delacour, and Viktor Krum—after the First Task. The purpose of the egg was to inform the champions of their next challenge: to retrieve something precious that had been taken from them and hidden in the Great Lake.
• Solving the Riddle: Harry Potter was the last champion to decipher the clue. After being advised by Cedric Diggory to “take a bath” with the egg, Harry took it to the Prefects' Bathroom. There, with a hint from Moaning Myrtle, he submerged the egg and himself, finally hearing the song's true message and learning the nature of the task. Both Cedric Diggory and Fleur Delacour also solved the riddle in this manner. It is implied Viktor Krum, likely with help from Igor Karkaroff, also solved it, possibly using a spell to hear the underwater message.

The lyrics of the song from the Golden Egg provided the full instructions for the Second Task. Come seek us where our voices sound, We cannot sing above the ground, And while you're searching, ponder this: We've taken what you'll sorely miss, An hour long you'll have to look, And to recover what we took, But past an hour — the prospect's black, Too late, it's gone, it won't come back.

• In the film adaptation of Harry Potter and the Goblet of Fire, the experience of hearing the song underwater is depicted with an ethereal, echoing female voice. (film)
• The lyrics in the film are abridged, omitting the final four lines that warn of the permanent loss of the hostage. The film's version is: (film)

Come seek us where our voices sound.

  //We cannot sing above the ground.//
  //An hour long you'll have to look,//
  //To recover what we took.// (film)