Here's a little trick I found at a tournament that saved my butt.
 
Use Bloodfire Infusion with any creature that states:
When ever this card is but into your graveyard from play, a black creature
token into play that has the same qualities as this one except without this
ability.
 
I used this with Penumbra Worm (a 6/6 with trample) and it did six damage to
every other creature, which, wiped out all the creatures, and Penumbra Worm
came back into play and it was still my turn. I was at 7 life and he was at
11 so i won the turn after that.