If you control 3 or more "Harpie Lady" and/or "Harpie Lady Sisters": Target as many monsters your opponent controls as possible, but not more than the total number of "Harpie Lady" and "Harpie Lady Sisters" you control; destroy those targets, and if you do, inflict damage to your opponent equal to the highest original ATK among those destroyed monsters (your choice, if tied). You cannot Special Summon monsters from the Main Deck or Extra Deck, nor conduct your Battle Phase, the turn you activate this card.
One of a few monster removals in current card pool, but the condition to use the card, having 3 or more Harpie Lady or Harpie Lady Sisters, is very difficult to be achieved especially under Speed Duel format to allow players have up to three monsters on the field.
But i did it Before trying to activate the spell. I thought you could not special summon after activating the effect. Man this card sucks if you can't even special summon Before activating this spell card..