Volibear, the Thunder's Roar

Fighter (Whenever this creature attacks, you may
have it fight target creature you don't control.)
Once per turn, when Volibear is dealt damage, it
gets +0/+X until end of turn, where X is half of
its toughness, rounded up. As long as this ability
is on the stack, players can't cast spells or
activate abilities that aren't mana abilities.
"Let the storm follow in my wake."