Hearthpwn

Too bad this expansion is almost over;  this Mecha'thun deck is the funk.  It has that secret sauce.  Might be my favorite Mecha'thun I've ever made.  Fails horribly against mega aggro decks 99% of the time.  However, this deck is mega fun to play and seems to be able to destroy most opponents if RNG is on your side (often even without!).  Basic Mecha'thun combo is discount it or Plague of Flames with Emperor Thaurissan and then it will cost 9 mana max to play Mecha'thun and then Plague of Flames.  If you're clever, play with Thaurissan and draws from the quest reward, which cost 0, along with a Galvanizer I threw in there.  Whenever you see an opportunity to use Emperor Thaurissan to reduce the cost of your other cards and Mecha'thun combo a different way (Coin, Galvanizer, Quest Reward Draw), that can lead to some pretty powerful plays and help eat through your deck.

Play around with different things and most importantly, HAVE FUN!