??? (Majora's Mask)

is a character in.

Biography
Each night at midnight, ??? emerges from the toilet of the Stock Pot Inn asking for paper. It remains until 6am. Link can give it any item made of paper, namely a Title Deed, the Letter to Kafei, or the Special Delivery to Mama. After doing so, ??? disappears and a toilet flush is heard. ??? re-emerges with a Piece of Heart that fell into the toilet.

When Link holds up the Piece of Heart, ??? imitates him by holding up its palm.

For whatever reason, ???'s voice is the exact same as Mikau's when Link first meets him at Great Bay.

Inspiration
The concept of a hand in the toilet is based on Japanese ghost stories where a hand grabs from beneath the toilet whenever someone sits in the bathroom.