It seems people regard this card as bad for some reason. Unless I didn't understand the meaning of the text as well as I thought, if you find a way to donate the card to your opponent, they will have to exile an increasing number of cards each turn (based on the number of age counters on the card), which sounds pretty OP to me. Assuming 60 cards a deck, they won't have a lot of turns left before they lose, no matter when you donated them the card.
http://gatherer.wizards.com/Pages/Card/Details.aspx?name=thought lash