Tirgahr, Growing Predator

Whenever Tirgahr deals combat damage, gain
that much life.
At the end of combat, Tirgahr deals damage to
target green creature or player, equal to the
amount of life you gained this turn.
Whenever a creature an opponent controls dies,
if Tirgahr dealt damage to that creature this turn,
exile it instead, and put a +1/+1 counter on
Tirgahr