Destiny HERO - Drilldark

If this card is Normal or Special Summoned: You can Special Summon 1 "Destiny HERO" monster from your hand with ATK less than or equal to this card's ATK on the field. You can only use this effect of "Destiny HERO - Drilldark" once per turn. If this card attacks a Defense Position monster, inflict piercing battle damage to your opponent.