Tangle Strider

Trample. Immense (As an additional cost to cast creatures with Immense you must sacrifice 2 creatures and 1 land you control).
Whenever Tangle Strider attacks you gain control of a target land opponent controls, this land becomes a Forest in addition to it's other types and may generate {g} or the mana color designated by the land type.
"They are the stewards of the forest, and they are taking it back one acre at a time"