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.
Yeah, that's why I thought... this dude could nuke the entire field with Last Gamble, but I don't see anyone playing it... there are some other decks that aren't as competitive as this one. Yet people reaches kog with them :D