Brutal Encounter

Target creature you control fights another target creature an opponent controls. If your creature
did not die, put a number of +1/+1 counters
equal to the toughness of the creature it fought.
If your opponent's creature did not die, give it a
number of -1/-1 counters equal to your
creature's power.
A chance encounter can sometimes lead to the answer
of who deserves to be called "Strongest".