Hearthpwn

Credit for this deck goes to Col Asmodai from twitch. He made this deck very early on in the Boomsday meta. It has been a fun deck on ladder, but in this brawl it's ridiculous.

Mulligan Guide:

Auto Keep: Devilsaur Egg, Necrium Blade, Fire Fly, Backstab

Auto Keep only with Coin or Backstab: Vilespine Slayer, SI:7 Agent, Elven Minstrel

Keep against Token Druid: Mossy Horror

Basic Plan:

Utilize the deathrattle on the Necrium Blade to get out a couple Devilsaur, Radioactive Ooze, or Mechanical Dragon onto the board. An example of an excellent opening hand is to go 2nd, and to have the Coin, Necrium Blade, Fire Fly, and Devilsaur Egg. With that kind of a hand you could coin out the Necrium Blade and swing at anything, then on turn 3 play the Devilsaur Egg and swing with the blade for a 2nd time, and you'll have an 0/3 Devilsaur Egg and 2 5/5 Devilsaur on the board. From there you can use your Fire Fly to trigger key combo cards such as SI:7 Agent, Vilespine Slayer, or Elven Minstrel. 

Healing:

You can use Zilliax as a buff on either the Blightnozzle Crawler, Mechanical Whelp, or Mechanical Dragon for 5-10 HP healing at times. Also note that if you want to cube Zilliax, just remember that if you use him as a Magnetic Buff, you can not get him back through cubing that minion, he has to be on the board as his own minion for that to work

Fun Combo;

If you have 9+ mana and have the three cards Carnivorous Cube, Necrium Blade, andLeeroy Jenkins you have a solid had for a nice and easy 33 dmg combo. You just play the Necrium Blade on turn 9+ and swing at anything. Next turn you play Leeroy Jenkins Most likely hit face for 6dmg, Cube the Leeroy, and swing at their face for another 3 dmg, and then (if you have the room) you'll summon another 4 Leeroy Jenkins for an additional 24 dmg (33 dmg in total)

So far it has been a very fun deck in the brawl, I totally recommend trying it out! Give the deck a like if you do!