A Spread of Rampant Green

Plant creatures you control are Forest lands in addition to their other types and have +1/+1.
{2}{g}: Search your library for a basic Forest card,
put that card onto the battlefield tapped, then
shuffle.
{x}{g}{t}: Destroy target nonland permanent with
mana value X or less, only green mana may be used
to pay for this ability. If X is 50 or more, you may
instead have target player lose the game.