Nature's Calling

Nature's Calling enters the battlefield with four
spirit counters on it.
At the beginning of each main phase, put one,
two, or three spirit counters on Nature's Calling.
If there are more than twelve spirit counters on
Nature's Calling, you lose the game.
{3}{g}, remove two spirit counters from Nature's
Calling: Target creature gets +3/+3 and trample
until end of turn.