Kermitwalker

All creatures are green in addition.
Muppets gain — {t}: Add {g} to your mana
pool equal to the Muppets you control.
{g}{g}: Target creature becomes Muppet
while Kermitwalker is in play.
{g}{g}{g}: All creatures become Muppets
while Kermitwalker is in play.
{g}{g}{g}{g}: Destroy all Muppets.