Merilia, Ally of the Beasts

Player
{g/u}, {t}: Target creature you control with a +1/+1 counter on it gains "Whenever this creature deals combat damage to a player, proliferate." until end of turn. (To proliferate, you may choose any number of permanents and/or players with counters on them, then give each a counter of a kind already there.)
Mana Pool - {u} or {g}