Instant 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
Only creatures in play when the spell is resolved are affected. This means that any creatures which come into play after this spell is resolved are not affected. [bethmo 1994/06/01]
The creature is destroyed if it does not attack because it simply cannot do so legally. For example, a Sea Serpent will be destroyed if it cannot attack because the opponent has no islands. [Aahz 1994/06/01]
You can use this effect on a creature you know won't be able to attack. For example, you can use it on a tapped creature. [Aahz 1994/06/01]
It will require creatures with Haste (see Rule 502.5) to attack since they are able, but it won't destroy them if they don't for some reason. [DeLaney 2000/03/14]
Extended tournaments (see Rule 803) have banned this card since 1999/10/01.
Quarta Edizione
(Uncommon)