Siren's Call (LEB) from Limited Edition Beta, available at 401 Games Canada.

• Rarity: Uncommon
• Finish: Normal
• Artist: Anson Maddocks
• Card Text:
  All of opponent’s creatures that can attack must do so. Any non-wall creatures that cannot attack are destroyed at end of turn. Play only during opponent’s turn, before opponent’s attack. Creatures summoned this turn are unaffected by Siren’s Call.