Pact of Blight

Put a -1/-1 counter on target creature, then draw a card for every 2 life you have lost this turn.

If you have not lost life this turn, proliferate twice.
(To proliferate, choose any number of permanents and/or players, then give each another counter of
each kind already there.)

"Once a pact is made, a Warlock’s thirst for knowledge cannot be quenched with mere study."
—Aimé, Alluring Æthermage