Garruk and Sarulf, Packleaders

Whenever Garruk and Sarulf deal damage to a
player, you may have a nonlegendary creature
card you own from outside the game become
your companion. (Companions can be put into your
hand from outside the game as a sorcery for {3} each.)
{1}{b}{b}, Sacrifice a permanent that wasn't in
your starting deck: Exile target nonland
permanent with mana value 3 or less. Put a
+1/+1 counter on Garruk and Sarulf.