If a creature starts its turn within 30 feet of the chang nam and can see the creature's shadow (which requires dim light or bright light), the chang nam can force the creature to make a DC 12 Constitution saving throw if the chang nam isn't incapacitated. The creature takes 7 (2d6) necrotic damage, or half as much on a successful save. A creature that isn't surprised can avert its eyes at the start of its turn to avoid seeing the chang nam's shadow and having to make a saving throw. If it does so, it can't see the chang nam until the start of its next turn, when it can avert its eyes again. If it looks at the chang nam in the meantime, it must immediately make the save. The chang nam's shadow cannot be seen in darkness or when vision is heavily obscured, and creatures have advantage on their saving throws when vision is lightly obscured.