Whenever a creature dealt damage by ~ this turn is put into a graveyard from play, put a blood counter on ~.
As long as ~ has a blood counter on it, it is a Vampire, has Flying, and whenever it deals combat damage to a creature, put a +1/+1 counter on it.
Remove a blood counter from ~: Put a +1/+1 counter on ~.
Whenever ~ deals combat damage to a player, put that many 1/1 black Bat creature tokens with Flying into play.
Whenever a creature is put into a graveyard from play, put a blood counter on ~.
At the beginning of your upkeep, sacrifice ~ unless it has a blood counter on it. Then remove a blood counter from ~.