Anyone who hears the song of a group of harpies must save versus spells or be charmed: move towards the harpies (resisting those who try to prevent it); defend the harpies; obey the harpies' commands (if understood); unable to cast spells or use magic items; unable to harm the harpies. A character who saves is unaffected for the rest of the encounter. Killing the harpies breaks the charm.