Wight River Vengeant

Retribution (Whenever a creature you control
dies, if it wasn't sacrificed, put a +1/+1 counter
on this creature.)
Whenever one or more +1/+1 counters are
placed on Wight River Vengeant, you may put
up to one -1/-1 counter on target creature.
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Blood for blood. Just, not my blood.