A character's mask is usually intended to obscure the face. In animation this used to also be a helpful cheat to draw something similar. In order to look less wooden it is very common for the mask to become a character's face. The eyeholes and even the shape of the mask will contort seamlessly depending on the character's mood. At the very least the mask will move as if painted on. This is especially true when a character's eyes are not drawn while in costume. A peculiar variant of this extends to characters who only have a skull for a head, and therefore have Expressive Eyesockets.