You gain the likeness of a harpy, as well as the powers of one. This trait allows you to cast the find familiar spell as an action once per long rest. The familiar summoned must take the form of a raven (it uses the raven statistics on page 335 of the Monster Manual) and it is a celestial instead of a fey. Additionally, after a minute of conversation with a humanoid, you can attempt to charm them. They must succeed on a DC 13 Charisma saving throw or be charmed by you.
Your tongue and teeth turn black and you grow black fledgling feathers on your legs, arms and other parts on your person of your choice. Additionally, when you meet a creature of your preferred sex, roll a d20. On a roll of 11 or higher, you are enamored by this person, and attempt to win him or her over in any way you can. If your advances aren't reciprocated, you feel despondent and heartbroken, until another love interest comes your way.