Blood Coin

Whenever a creature dies, put a blood counter on
Blood Coin.
At the beginning of your upkeep, flip a coin
until you lose a flip or have flipped it X times,
where X is the number of blood counters on
Blood Coin. You gain life equal to the number
of coin flips you won this way this turn.
{t}, Remove X blood counters from Blood Coin:
If you won a coin flip this turn, target creature
gets +X/+X until end of turn.