Hearthpwn

I don't know if I've ever had this much fun laddering. You basically play Necrium Apothecary and win. Careful to have a zero cost spell in hand to activate (combo) him and when he dies, you get an entire board of big scary dragons. I've done it occasionally on turn 3 (with the coin and a counterfeit coin), but usually it will happen on turn 4 or 5. 

If you can play Necrium Blade on turn 3 and attack, you can play Necrium Apothecary on turn 4, and when you attack with the blade again, the dragons shall invadeth! But, the blade is not necessary for a win. It just may take another turn to kill off your Apothecary without using Coerce or another method.

If you don't have a certain dragon in your collection, just substitute it for a big ugly dragon of your choice.

I added a single Witchwood Piper to the deck to pull the Necrium Apothecary, since it's equally as important of a card as Deathwing, Dragonlord. Without it, you are up a creek, so, Witchwood piper helps a lot. Adding it was perhaps the most pivital change I made to this deck. The Witchwood Piper pulls the Necrium Apothecary 100% of the time if it's still in the deck. This has saved me many times. 

There is a lot of card draw in the deck. As long as your health is not low, try to hold back a draw card until just AFTER the first wave of dragons hits the board to draw more dragons into your hand in clears your board. Deathwing, Dragonlord will then pull them right out. Togwaggle's Scheme is great for loading more Deathwing, Dragonlord's into the deck, and you can use the second apothecary just like the first!

Plus, there's nothing more demoralizing and savage than your opponent watching you send 9 more Deathwing, Dragonlord's into your deck.

Mulligan Guide: 

DO NOT keep Deathwing, Dragonlord. You will need to pull it with the Apothecary for the Apothecary to work. Hold one Necrium Apothecary ALWAYS. If it is not there, hold one card draw, and dig for the Apothecary. If you have it, dig for a way to kill it (Coerce or Necrium Blade), and if you have that, dig for a zero cost card to activate the Apothecary's combo requirement. Always keep Gone Fishin' and the Sphere of Sapience. If you have a dragon in hand AND Candle Breath, you may keep them, since you'll pull 3 cards on turn 3 and cycle the deck.

Updates:  (Too many to list here over the years)

Removed Sleepy Dragon and replaced it with Roll the Bones then replaced that with Coerce. It helps kill off the Apothecary, and is also useful against your opponents' minions.

I removed Blatant Decoy, and brought back Anka, the Buried. It was fun to pull Blightborn Tamsin before your opponent could play the battlecry, but the Blatant Decoy often caused other issues in the deck. 

Enjoy those turn 4 wins!