Briseis, the Stolen

Briseis can't attack or block.
Spells you cast cost {2} less to cast.
When a creature an opponent controls deals
combat damage to you, that creatures controller
gains 2 life, draws a card and gains control of
Briseis.
When you lose control of Briseis, creatures you
control becomes tapped and don't untap during
your next untap step.