Flesion, The Eviscerator

+2: Remove a +1/+1 counter from target creature you don't control, and put a -1/-1 counter on target creature you control.
0: Remove a -1/-1 counter from target creature with persist.
-7: All +1/+1 counters become -1/-1 counters, and all -1/-1 counters become +1/+1 counters. (these effects occur at the same time on the stack.)