Arrogant Warrior

Whenever a creature an opponent controls dies,
if it was dealt damage by Arrogant Warrior this
turn, put a +1/+0 counter on Arrogant Warrior.
Boast - {x}{r}: Arrogant Warrior deals {x} to
target creature an opponent controls. This ability
costs {1} less to cast for each +1/+0 counter on
Arrogant Warrior. (Activate only if this creature
attacked this turn and only once each turn.)