Hearthpwn

This deck so works in 2018! Slitherspear was the last boss for me to clear for my League of Explorers cardback. I'd tried a dozen different decks. This deck finally got it done for me. Followed the suggestions and got it done on 5th try. Thanks! 

This worked when nothing else would. I used Stoneskin Basilisk instead of Emperor Cobra, and it worked on maybe the 4th or 5th try. 

Advice:

• Use Dagger on the first minion. Hold off the next few with a combination of silence and poison minions, Betrayal, and Annoy-o-Tron
• Gang Up is for Coldlight Oracle 
• Protect Brann Bronzebeard  at all costs
• Coldlight + Preparation + Vanish is a strong midgame play to get minions off the board and take control with poison minions, etc.
• The turn right before you win will involve the computer having a board full of minions but a nearly empty deck, then you drop Brann and multiple Coldlights. 
• It's very hard to win this game without an early Coldlight + Shadowstep, Brann, and both copies of Vanish.

Legit deck.  Still working in early March 2018.  Took a little bit of doing.

You absolutely have to emphasize getting those early poisonous minions on to the board or you will fall behind.  Try and hold off on using a Coldlight Oracle until you've got something to get it back.  Whether it's Shadowstep, Gang Up, or you simply have the second one handy, it's vital to make sure that you start milling at the right time.  If you find yourself mid-game with a clean enemy board, but no mill, you're not going to win because you'll still be without some way to kill him.  And you can only stall with Vanish twice, so..

Worked great, subbed in Stoneskin Basilisk since I didn't have Patient Assassin. :)

As of K&C Meta this deck is still rock solid. Did it after 3 tries. Even though I was missing some cards as long as you have the core of the deck it works ok. As I was lacking antique healbot I put in cult apothecary (though I never end up using them) and two mistress of mistures because I was lacking one owl and one emperor cobra

Took me 4 attempts with this deck to defeat the boss. I replaced both Emperor Cobra 's with Stubborn Gastropod as I didn't have Emperor Cobra.

That's a good sub!

Worked for me on like the 5th try or so. I tried another mill deck like 20ish times and never even got close... It was really close in the end but I won, thanks!

First off, this boss is absolutely ridiculous, and we all know it. The RNG fest bosses are painstakingly annoying, but this list has been the most successful Mill Rogue list I've seen to date. Thanks for posting.