Mushroom Forest

Play this card by exiling a land you control with
6+ mushroom counters on it. This card enters the field tapped. Once per turn during your upkeep add a mushroom counter to this card. This card can not be destroyed by mushroom counters.
{t} add {1} to manapool, transfer all mushroom counters on this card to any other cards in play, then proliferate. (You choose any number of permanents and/or players with counters on them, then give each another counter of a kind already there.)