Boros Challenger [Mystery Booster]

Set: Mystery Booster Type: Creature — Human Soldier Rarity: Uncommon Cost: {R}{W} Mentor (Whenever this creature attacks, put a +1/+1 counter on target attacking creature with lesser power.){2}{R}{W}: Boros Challenger gets +1/+1 until end of turn. "Send your champion. I could use a light workout."