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.
15-08-2010
wotc
You can sacrifice Viscera Seer to activate its own ability.
Random a card of Magic: The Gathering (MTG), but you can also roll the D20 dice, random a Planeswalker, have fun with the random rules and more.