Triumphant Emergence

Whenever an opponent casts a creature spell, you gain life equal to it's converted mana cost.
{x}{x}{x}{g}{g}{g}: Gain control of that creature until end of turn. It gains haste. At the beginning of your end step, you gain life equal to the amount of damage dealt by that creature this turn.
{x}{x}{x}{x}{x}{g}{g}{g}{g}{g}: Gain control of x creatures until end of turn, then you gain life equal to the amount of creatures you control.