Viscera Seer | Magic: The Gathering
Formats Viscera Seer is Legal in
Official Oracle Text for Viscera Seer
Official Rulings for Viscera Seer
8/15/2010 : If you sacrifice an attacking or blocking creature during the declare blockers step, it won't deal combat damage. If you wait until the combat damage step, but that creature is dealt lethal damage, it'll be destroyed before you get a chance to sacrifice it.