Use dire frenzy on a stonetusk boar or a hound from Unleash the Hounds. Kill a helpless hatchling (with goblin prank, e.g.) with a dire frenzied minion in your hand to reduce its cost to 0. Then for 10 mana, play your 0 mana beast followed by Zul’jin. If you manage to play all of your minion buffs before Zul’jin, this combo can do more than 20 damage with 1 minion.