Unstable Frontier | Magic: The Gathering
Formats Unstable Frontier is Legal in
Official Oracle Text for Unstable Frontier
: Target land you control becomes the basic land type of your choice until end of turn.
Official Rulings for Unstable Frontier
2/1/2009 : The affected land loses its existing land types and any abilities printed on it. It becomes the chosen basic land type and now has the ability to tap to add one mana of the appropriate color to your mana pool. Unstable Frontier's ability doesn't change the affected land's name or whether it's legendary or basic.