Card Blocker (ANPR-EN093) [Ancient Prophecy]

When this card is Summoned it is switched to Defense Position. When a face-up monster you control is selected as an attack target, you can change the attack target to this card. When this card is selected as an attack target, you can send up to 3 cards from the top of your Deck to the Graveyard, to give this card 500 DEF for each of those cards, until the End Phase.