"Skull Kid" is a character from Nintendo
's Legend of Zelda
series of video games
Children that get lost in the enchanted forrest become skull-kids. They loose their face and become permanent residents of the forest.
In Occarina of Time a skull kid is part of the Happy Mask shop trading sequence. He will buy a spooky mask off you.
In Majora's Mask, a skull kid steals a powerfull magical mask from the Happy Mask man. This mask compells him to do all sorts of evil things.