M. Bison, Psycho Power

Whenever M. Bison, Psycho Power enters the
battlefield or attacks, put two -1/-1 counters on
target creature.
M. Bison, Psycho Power's power is equal to the
number of -1/-1 counters on all creatures.
When M. Bison, Psycho Power dies, you may
sacrifice another creature with a -1/-1 counter.
When you do, return M. Bison, Psycho Power to
the battlefield under its owner's control.