Trumpet Blast | Magic: The Gathering
Formats Trumpet Blast is Legal in
Official Oracle Text for Trumpet Blast
—Zurgo, khan of the Mardu
Official Rulings for Trumpet Blast
10/1/2009 : An "attacking creature" is one that has been declared as an attacker this combat, or one that was put onto the battlefield attacking this combat. Unless that creature leaves combat, it continues to be an attacking creature through the end of combat step, even if the player it was attacking has left the game, or the planeswalker it was attacking has left combat.
10/1/2009 : Even though Trumpet Blast affects only attacking creatures, the bonus will remain for the rest of the turn.
10/1/2009 : If Trumpet Blast is cast before attackers are declared or after combat ends, it won't do anything.