Siren's Call | Magic: The Gathering
Formats Siren's Call is Legal in
Official Oracle Text for Siren's Call
Creatures the active player controls attack this turn if able.
At the beginning of the next end step, destroy all non-Wall creatures that player controls that didn't attack this turn. Ignore this effect for each creature the player didn't control continuously since the beginning of the turn.
Official Rulings for Siren's Call
10/4/2004 : The creature is destroyed if it does not attack because it simply can't do so legally.
2/1/2009 : This will destroy creatures that weren't able to attack because they had been previously tapped.
9/20/2013 : If a turn has multiple combat phases, this spell can only be cast before the beginning of the Declare Attackers Step of the first combat phase in that turn.