Umitar, The Beast Charmer

Eminence - On each player's end step, if they
control the creature with the highest power, they
may draw a card.
{g/u}, {t}: You may cast creature spells until end of
turn as though they had flash.
{3}{r}{r}, {t}: Target creature with the highest
power deals damage equal to its power to its
controller, the controller may instead sacrifice
the creature and draw a card.
Umitar's power is equal to the amount of
mana used to cast him.