Ball Weevil

Whenever a player casts a spell, amass Balls 1.
(To amass Balls 1, put a +1/+1 counter on an
Army you control. It's also a Ball. If you don't
control an Army, create a 0/0 green Ball Army
creature token first.)
Sacrifice a Ball, {t}: Each creature target
player controls gets -X/-X until end of turn,
where X is the Ball's power.