Mermail Abyssbalaen (Ultimate Rare)

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