Siren's Call

Instant, U (1)
Play Siren's Call only during an opponent's turn and only before attackers are declared.
Creatures the active player controls attack this turn if able.
At end of turn, 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.¹
Illus. Anson Maddocks

Gatherer Card Rulings

• 10/4/2004: It will require creatures with Haste to attack since they are able, but it won't destroy them if they don't for some reason.
• 10/4/2004: The creature is destroyed if it does not attack because it simply can't do so legally.
• 8/1/2008: A creature required to attack or block if able in a given turn only has to do so during the first combat phase that turn in which it's able. Basically, each combat phase in that turn, you ask "did this creature attack/block this turn?" and "can this creature attack/block this phase?" If the answers are "no" and "yes" respectively, then it must attack or block as required. This is important if a turn somehow gains extra combat phases.
• 2/1/2009: This will destroy creatures that weren't able to attack because they had been previously tapped.

Format Legality	Legal in Vintage, Legacy Banned in Extended, Standard
Printings (5/18)	Fourth Edition (Uncommon) Revised Edition (Uncommon) Unlimited Edition (Uncommon) Limited Edition (Beta) (Uncommon) Limited Edition (Alpha) (Uncommon)