Woodwraith Corrupter
Creature — Elemental Horror
, 
: Target Forest becomes a 4/4 black and green Elemental Horror creature. It's still a land.
"Its darkened sap penetrates natural fibers and spreads its own genes. Emulation experiments are underway." —Simic research notes
Greg Staples
Rulings
A noncreature permanent that turns into a creature can attack, and its {T} abilities can be activated, only if its controller has continuously controlled that permanent since the beginning of their most recent turn. It doesn’t matter how long the permanent has been a creature.
(wotc • 2008-08-01)
The effect has no stated duration, so a land turned into a creature this way continues being a creature as long as the land is on the battlefield.
(wotc • 2005-10-01)
Rulings
A noncreature permanent that turns into a creature can attack, and its {T} abilities can be activated, only if its controller has continuously controlled that permanent since the beginning of their most recent turn. It doesn’t matter how long the permanent has been a creature.
(wotc • 2008-08-01)
The effect has no stated duration, so a land turned into a creature this way continues being a creature as long as the land is on the battlefield.
(wotc • 2005-10-01)