Hellhard Eight

Trample, Haste
Creatures you control have indestructible
Discard a card: After this phase, there is an additional combat phase. At the beginning of that phase, sacrifice a creature that attacked this turn.
Search your library for a creature card with base
power less than or equal to the sacrificed
creature's power, and put that card onto the
battlefield tapped and attacking. Activate
this ability only during your turn.