"A small box of wax crayons."
Box of Crayons is a trade item that may be used to change the color of various objects, including your character. When used you will be prompted with "What do you want to draw?" After entering what you want to draw you will be asked to select a direction around you to draw on, which will be colored randomly. To change the color of your character press '5' on the numpad when asked which direction to draw in. Do note however, that directing toward '5' will sometimes cause you to draw on the floor seemingly at random.
This trinket can be deceptively useful for a character who often relies on allies, as it is a cheap and lightweight way to make companions visually distinct from similar creatures.
Box of Crayons is unusual in that it must be examined/identified like an artifact, but once identified it can't be disassembled.