Man's Best Friend

Multikicker {w} and/or {b} (You may pay an additional {w} and/or {b} any number of times as
you cast this spell)
Flash
When Man's Best Friend enters the battlefield regenerate up to {x} target human creatures for
each time this spell was kicked {w}, and give -1/-1
to up to {x} target creatures until end of turn for
each time this spell was kicked {b}.
"Good boy" - Owner