Yesim, Loyal Advisor

+3: Put a plus +1/+1 counter on target creature you control, and put a -1/-1 counter on target creature you don't control.
-3: You gain 10 life.
-X: Yesim, Loyal Advisor deals X times two damage to target creature. You gain life equal to the damage dealt this way. create that many 1/1 bats.