Sirènemure Abyssbalaen LTGY-FR083

You can discard 4 other "Siren Mermaid" monsters to the GY, Special Summon this card from your hand. When you do: Target a number of your opponent's cards up to the number of "Siren Mermaid" monsters in your GY (if possible), this card gains 500 ATK, and if it does, destroy those targets. You can Tribute 1 other "Siren Mermaid" monster you control in face-up Attack Position; this turn, this card gains this effect: At the start of the Damage Step, if this card battles a Defense Position monster, destroy that monster.