Rat Gladiator

Firststrike
Reduce all damage dealt to rats you control by 5. When a rat is dealt damage put that many +1/+1 counters on each rat you control. Rats you control have Firststrike. Rat Gladiator cannot block or attack unless you have more than 15 creatures.
{b}{b}: Deal five damage to target creature you control.
{t}: Rat Gladiator fights target creature.