Greedy Gambler

{b}: Roll a d20.
1-4: Remove all gamble counters from
Greedy Gambler. Lose 5 life.
5-20: Gain black mana equal to the amount of
gamble counters on Greedy Gambler. Put a
gamble counter on Greedy Gambler. You may activate this ability again for no cost.
Greedy Gambler gains +1/+1 for each
gamble counter on it.