Siren's Call [Beta Edition] Scars of Mirrodin sacrifice Koskun Falls unless you

sacrifice Koskun Falls unless you tap an untapped creature you control

Set: Morningtide Type: Enchantment Rarity: Rare Cost: {1}{G} Whenever a creature enters the battlefield under your control

{T}: Tap target artifact

If it's a land card

Siren's Call [Beta Edition] Scars of Mirrodin sacrifice Koskun Falls unless youSet: Beta Edition Type: Instant Rarity: Uncommon Cost: {U} Cast this spell only during an opponent's turn, before attackers are declared. 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.