Skull Kid

The Skull Kid is what becomes of children getting lost in the Lost Woods, and appears in Ocarina of Time, Majora's Mask and Twilight Princess. They first interact with Link in Ocarina of Time, and later a Skull Kid plays a major role in Majora's Mask. Skull Kids dress in a red cloak and hat covering an underlayer of clothing comprised of a straw-like material, and play a flute, which they can also use as a weapon to shoot projectiles.

Ocarina of Time
In Ocarina of Time, a Skull Kid can be found in the Lost Woods, in the area directly to the left of the entrance room. Whenever Link approaches, the Skull Kid will disappear from the area. To circumvent this, Link can befriend the Skull Kid by playing Saria's Song while standing on top of the stump across from the Skull Kid's position, and you will receive a Piece of Heart as a gift. Another two Skull Kids can be found in the area directly to the right of the entrance, where there is a mini-game in which Link repeats a sequence of notes on his ocarina to win a Piece of Heart. It is not known whether these are apparitions of the Skull Kid in the area on the left of the entrance, or separate Skull Kids entirely.

While Z-Targeting, Navi mentions that the Skull Kid seems unhappy to have no face. Upon first seeing Link wearing the Skull Mask, the Skull Kid comments that he would like it to make him appear a little tougher. Link is able to sell him the mask as part of the Mask Trading Sidequest, but the Skull Kid pays just ten rupees when the wholesale price is twenty, leaving Link to cover the difference.

If Link encounters the Skull Kid as an adult, he will be attacked with Deku Seeds shot from the Skull Kid's flute. Navi says that he is attacking because he does not like adults. It's rather cruel, but if you slash him with the Biggoron's Sword or Giant's Knife he will collapse and disappear, rewarding you with an orange rupee.

Majora's Mask
While Link first encounters the Skull Kid in the Lost Woods of Hyrule, dialogue in Majora's Mask suggests that the Skull Kid is originally from Termina.

In the past, the Skull Kid was befriended by the Four Giants. After a time, however, the Giants left Termina and the Skull Kid was alone, motivating him to seek attention by causing mischief and playing pranks on people.

Preceding the events of Majora's Mask, the Skull Kid met with Tatl and Tael and stole Majora's Mask from the Happy Mask Salesman. Shortly afterwards, he ambushed Link and attempted to steal the Ocarina of Time. During this confrontation, the Skull Kid transformed Link into a Deku Scrub.

Over the course of the game, Link gathered the power of the Giants and freed the Skull Kid from the evil influence of Majora's Mask. During the end credits the Skull Kid is reunited with the Giants and tells Link that he remembers befriending him in Ocarina of Time.

His skin appears to be made of wood.

Twilight Princess
In Twilight Princess, the Skull Kid leads you through the Lost Woods portion of the Sacred Grove until you reach the remains of the Temple of Time where you will pull the Master Sword from it's alter. He plays a cruel game of Hide-and-Seek, as you have to find him several times before he will lead to where you need to be and you have to fight his puppets all the time. He will help you navigate the Lost Woods a second time, this time leading you to through different areas to take you to the Temple of Time dungeon. His hiding spots will be more difficult to find. However, two factors give away his location: the light of his lantern, and the sound of his horn playing Saria's Song. Although the Skull Kid never physically attacks you, he will summon Puppets to attack you. Every time he is hit in battle he will summon more puppets to attack you, but he can be beaten quickly with a bow and arrows. After defeating him the second time he will tell you that was fun and vanish.

One may note that his eyes and face look very similar to those of the Moon from Majora's Mask, albeit with a mischievous smile instead of the Moon's trademark scowl. Due to the fact that he knows Saria's Song, it is possible that he is the same Skull Kid from OoT & MM.

A Skull Kid appears in A Link to the Past as well.