Ritual of Rebirth

As an additional cost to cast this spell, exile a
snake creature you control.
You gain life equal to the exiled creature's
toughness and draw cards equal to its power.
Then, put 3 egg counters onto the exiled
creature. At the beginning of each upkeep,
remove an egg counter from the exiled creature.
When all egg counters have been removed,
put the exiled creature into play with X +1/+1
counters on it, where X is the number of cards
in your graveyard.