Hearthpwn

May require some fine tuning, but I'm already 10-1 with this deck vs 2 different types of Rogue, Control Warrior, Mages and Control Shaman, so I thought I'd share it. You just get Mecha'thun down to 9 Mana, empty the rest of your hand and deck, then use Grim Rally as the finisher.

Changelog

05/14/19

• +1x Aranasi Broodmother and -1x The Soularium, because I found that the taunt and healing was more important, and that you're very likely to auto-lose when Soularium is in the bottom 3 cards of your deck, and it's just a dead early draw until super late game.
• +1x Acidic Swamp Ooze and -1x Harrison Jones, because Harrison was a bit too heavy to dump from your hand when the time comes, and has almost zero effect against Mages, Priests and most Shamans. You can get an ooze out earlier for board trades, or combo it with Lord Godfrey

Tips

• It's okay if you run out of demons in your deck for Sacrificial Pact as long as you still have a Sense Demons, since it adds two 1/1 imps to your hand. But you should still pay attention to how many are left as the match continues, because you can lose if you can't cast both of them.
• Remember... Nightmare Amalgam is both a demon and a mech, so it has double synergy in this list. That makes it viable for both Sacrificial Pact and Zilliax, so it's like a "craft-your-own" Shirvallah, the Tiger, except that you can also get rid of it for 0 mana which heals you for 5 additional hp in the process (if ever needed). This also means any magnetic effects you place on it can easily be undone just before (or even during) your combo turn, provided your opponent doesn't kill it for you.
• Without The Soularium in this list, you really only need one Galvanizer to land on your Mecha'thun. But there are two in this list anyway as a counter to Hecklebot, and because it combos well with Nightmare Amalgam and Zilliax setups, without having to wait to draw Mecha'thun. It just adds a lot of consistency/flexibility.
• If you can, try your best to save either a Twisting Nether or a Mortal Coil as the final card you play before your combo turn, depending on whether or not you believe your opponent has been saving an Unseen Saboteur in their hand. If they panic and play it too early, you still have a 50% shot of winning. And if they don't play it early, and you have Mortal Coil and an 8-mana Mecha'thun, you win regardless with Mecha'thun + Mortal Coil + Grim Rally!