Bor, Savage Berserker

Creatures you control have unleash. (You may have this creature enter the battlefield with a +1/+1 counter on it. It can't block as long as it has a +1/+1 counter on it.)
Creatures you control get +3/+0 trample and haste as long as they have a counter on them.
Creatures without counters on them cannot block creatures with counters on them.