Well, take the Penumbra ability in Apocalypse (When
x is put into a graveyard from play, put a equivalent black creature in
Now, take Lifeline, a Rare in Urza's
Whenever a creature is put into a graveyard and
another creature is in play, return the first creature from that graveyard
to play under its owner's control at the end of turn.
So, whenever your penumbra creature dies, you'll
get it back at the end of the turn, since its shadow version will still be in
play, assuming it hasn't been killed somehow.
However, you have to make sure your OPPONENT
doesn't get the benefits of lifeline, get some cards that remove creature cards
from opponent graveyards. Phyrexian Furnace, Night Soil, and Eater of the
Dead are good choices. If you can't get any of these out, just hope you
outnumber your opponent in creatures. If you want, you can use Mortuary
instead of Lifeline, but that'll seriously slow down your library (trust
Hope somebody uses this.