That Which Remains

At the beginning of your end step, exile all
creatures you control without petrified counters.
For each creature exiled this way, draw a card.
When a creature you control dies, you may cast
it from your graveyard without paying its mana
cost if it didn't have a petrified counter on it.
If you do, put a petrified counter on it.
{1}, Remove a petrified counter from a creature
you control: Target creature becomes an
artifact and loses all other card types.