The Sign Painter is an unseen character responsible for writing the signs seen throughout World of Goo
. The messages seen on his signs vary from helpful hints to story advancement, often helping the player understand the challenge presented at each level. The Sign Painter's signs are generally filled with humour, as he notes that the goos are partially aware of the fact that they are in a physics simulator game, or about the strange characteristics of some goos. The Sign Painter also leaves an ominous feeling about the levels, as the signs are often placed in strange or hard to reach places, it gives a mysterious air about him.