Woodwraith Corrupter
Ravnica: City of Guilds — rare
Creature — Elemental Horror
Woodwraith Corrupter rulings:
2008-08-01: A noncreature permanent that turns into a creature can attack, and its 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.
2005-10-01: 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.