Sangromantic Infusion

At the beginning of your upkeep, you lose 1 life
and create a Blood token. (It's an artifact with
"{1}, {t}, Discard a card, Sacrifice this artifact:
Draw a card.")
As an additional cost to cast creature spells, you
may sacrifice any number of Blood tokens. If you
do, that creature enters the battlefield with that
many additional +1/+1 counters on it and gains
haste until end of turn.