Fossil Dragon Skullgar [BLAR-EN010] Secret Rare

1 Rock monster + 1 Level 4 or lower monster in your opponent's GY
Must first be Special Summoned with "Fossil Fusion". If this card attacks a Defense Position monster, inflict piercing battle damage. You can banish this card from your GY; add 1 "Fossil Fusion" from your Deck to your hand. You can only use this effect of "Fossil Dragon Skullgar" once per turn.