Kill the Messenger

Cast only before blockers are declared. For each attacking creature you control, exile a card off the top of your library, and place it under each attacking creature. At the end of combat, for each surviving creature, put the card under it into your hand. Any creatures that were removed from play by any means those cards remain exiled.
Massacre- At the end of your combat phase, if three or more creatures died this combat, draw an additional for every card you put in your hand.