Boros Keyrune | Magic: The Gathering
Formats Boros Keyrune is Legal in
Official Oracle Text for Boros Keyrune
: Boros Keyrune becomes a 1/1 red and white Soldier artifact creature with double strike until end of turn. (It deals both first-strike and regular combat damage.)
Official Rulings for Boros Keyrune
4/15/2013 : Activating the ability that turns the Keyrune into a creature while it's already a creature will override any effects that set its power and/or toughness to another number, but effects that modify power and/or toughness without directly setting them will still apply.