To pull of the combo, you need to draw a LOT, so primary target during the mulligan, are drawing cards.
Against aggro, you should search for Spirit Lash woth Thalnos, to be able to clear the board and heal yourself on turn 4.
See under the "aggro" section! You must control the board.
Against other combo decks the only objective is to draw more.
Hey there! I theorycrafted this “OTK” priest deck – it’s more like 2-3TK – which I want to try after the new expansion starts. I made another version of it previously, right after the Boomsday Project was released but it was not really effective. The combo involves 6-7 minions so a large draw package is included: Northshire Cleric, Power Word: Shield , Acolyte of Pain alongside with Wild Pyromancer and Circle of Healing. Loot Hoarders and Bloodmage Thalnos with Spirit Lash for a better chance to survive against aggro. The plan is to take down the enemy to 15 health with Alexstrasza after you draw the combo pieces.
Than play Reckless Experimenter, Spiritsinger Umbra and the two Goblin Bombs with the Leper Gnomes. that is 16 damage. To pull this off you need the opponent to stay on 15 health so to make it more flexible I added the new priest spirits, Spirit of the Dead. If this combo is not enough because of healing and armor of you opponent, you can drop one of them with the Reckless Experimenter and the Augmented Elekk.
In this case you will deal only 8 damage, but you will have the opportunity for deal a lot more. After this you can refill your hand with Bwonsamdi, the Dead, which will draw you 8 dudes from you deck. After that you can make another turn with the other Reckless Experimenter and Spiritsinger Umbra. In this case you can play five dudes with deathrattles triggered twice which gives you another 20 damage. That is 28 damage in total.
It is hard for most calasses to heal this much in 1 turn but in case If it is still not enough damage, you can play the other Spirit of the Dead and four dudes – which means plus four more dudes to your deck – but after this it harder to deal the damage from your hand because there is a good chance that both of your Reckless Experimenters will be dead and you won’t have Bwonsamdi, the Dead to refill. That is why I run Zola the Gorgon. You will have a chance to copy either a Reckless Experimenter or Spiritsinger Umbra if you need more damage, or even Bwonsamdi, the Dead for more refill if you still have Bloodmage Thalnos and a Spirit Lash.
Seems like a fun deck for me which has more chance in my oppinon with spirit package and Bwonsamdi, the Dead.
We’ll see how it works.