Text (DK+errata): {Tap}, Sacrifice ~this~: The next time a source of your choice would deal damage to you this turn, it deals half that damage, rounded up, to you instead. [Oracle 2005/08/01]
Prevents half the damage from that source which is currently unprevented. So two of them will result in 1/4 damage, not zero damage. This is because you apply them sequentially, not simultaneously. [D'Angelo 1999/08/01]
Extended tournaments (see Rule 913) have banned this card since 1999/10/01.
