Tribute to the Dragon

Enchant player.
At the beggining of enchanted player's upkeep,
that player puts a hoard counter on this
permanent. For each hoard counter,
that player may pay 2 life or sacrifice a creature.
If the player can't, it loses 1 life for each hoard
counter.
{2}: Add one hoard counter on this permament.
Any player may activate this ability on their turn, and only once per turn.