Sadistic Ritual

Destroy target creature. If that creature had
power 3 or fewer, you may pay {b} to destroy
another creature. As long as the last creature
you destroyed from this card's effect had power
3 or fewer, you may pay {b} to destroy another
creature.
Plague doctors are like human carrions, descending on
the weak and the deceased, yet they have far more in consideration than their own sustenance