??? (Majora's Mask)

??? is a gray-colored hand that seems to live inside of toilets wherever he or she is found.

Majora's Mask
After midnight in Majora's Mask, it reaches out of the toilet next to the reception door at the Stock Pot Inn. In return for a piece of paper (i.e. one of the Title Deeds, the Letter to Kafei from Anju, or Express Mail), ??? will reward Link with a Piece of Heart.

No one knows the true origin or name of ???. It might be speculated that perhaps this person fell in and couldn't get out.

Oracle of Ages
In Oracle of Ages, in the past, ??? is another gray hand that needs toilet paper. If Link gives the Stationery to him, as part of a trading sequence, he will give Link a Stink Bag which is needed to clear the sinuses of a Tokay Cook.

Link can torture him in various ways, such as putting seeds in the hole he dwells in.
 * Mystery Seed: "Wh-What?!?"
 * Ember Seed: "Ooo... hot!"
 * Scent Seed: "Ewwww!"
 * Gale Seed: "My head spins!" (This can only be done by using the Roc's Feather to jump over the hole and dropping the seed before falling.)
 * Link cannot use a Pegasus Seed on ???.
 * If Link pushes the chamber pot into the hole: "Nooooo!"
 * Bomb: *explodes* "Koff!"
 * Bombchu:"???" *explodes* "Koff!"

Link is unable to survive the fall into the hole where ??? is found.

Skyward Sword
??? returns in Skyward Sword, this time colored blue and found in the bathroom of the Knight Academy, once again requesting paper. Cawlin gives Link a love letter to give to Karane, but Link may instead choose to give the letter to ???. If he does so, ??? will believe that the love letter was meant for itself, and will lovingly stroke Cawlin when he sleeps at night. Link will receive 5 Gratitude Crystals for helping ???.

In this game, ??? is revealed to be female, as people in Skyloft remark that they hear a woman sobbing in the dormitory. Also, ??? is revealed to be a disembodied hand.

Trivia

 * ???'s sound clips in Majora's Mask are the same as that of Mikau's when Link first meets him at Great Bay.
 * ??? appears to be similar to the many hands of the Dead Hand mini-bosses from Ocarina of Time. Perhaps ??? is the Terminan counterpart of these hand enemies.
 * Another "hand" character similar to ??? appears in A Link to the Past. This hand was a thief before being cursed in the Dark World.
 * Although ??? is never given any real name, he is referred to as "" in the Japanese version of Oracle of Ages.
 * In Skyward Sword, ??? resembles Master Hand from the Super Smash Bros. series.