"Dark spirits, twist the trees, foul the lake and  curse this land!"

Greetings, fellow Hearthstoners. This is my first guide and I honestly don't know if it will result good, but i'll give it a shot.

Now, prepare yourselves for the return of Hagatha!

As the title says, this is a control-focused Shudderwock Shaman, meaning that you want to take the game as far as possible when you're the strongest. As such, the obvious counters to this deck will be heavy aggro ones, such as Zoolock; lucky for us, this new yearly rotation will get us rid of annoying past decks such as odd Paladin.

As a Shudderwock deck, we want to keep the good-ol' strategy: play as many battlecry minions as possible before unleashing our fueled Wock. Through (ideally) most of the game we will be accompanied by our favorite witch, Hagatha the Witch, which will provide us countless backup random spells that could potentially save us from a lethal, as well as fueling our Shudderwock for clearing the board.

Now, for the proper stages and guide itself:

She has come back... and stronger than ever!

Mulligan stage:

Always aim for Hagatha's Scheme. For this stage you'll want to keep at least 1 card drawer, such as Mana Tide Totem or Far Sight, as well as 1-drops like Sludge Slurper and EVIL Cable Rat. This is regardless of the class and its deck archetype. If possible, a dream-like mulligan would include 1 card drawer, 2 one-drops and 1 Hagatha's Scheme.  If you have luck and draw both Hagatha's schemes, the better.

Early stage (1-4 mana crystals)

What we want to do in this stage is to, basically, avoid losing by playing as many spells within the 4-mana pool and battlecry minions as necessary. The next stage is actually when we start getting stronger. This includes playing cards like Spellward Jeweler, Potion Vendor and all lackeys earned through Sludge Slurper and EVIL Cable Rat. Don't be afraid on sending them all out, for we have our fellow Wock to repeat their battlecries. Given our lack of taunts, we have to be extra careful with any enemy minion on board as we don't want a flooded, and possibly lethal one.  Also if the enemy board is packed with minions, our Mind Control Tech will hopefully work miracles.

Middle stage (5-7 mana crystals)

This is where we turn the table upside down, as unleashing our Hagatha's Scheme (hopefully, if available) will potentially clear the board. Also, play Swampqueen Hagatha as soon as you can, for the next two spells of the summoned terror will be a huge advantage. If enough worthy friendly minions are on board, and taking account of the circumstances,playing Barista Lynchen could be a game-winning factor; see, this card has a huge synergy with our deck, and if we grab our enemy by surprise, we could generate extra amounts of value that may be able to put us at a seemingly unreachable advantage. However, if playing against another heavy control deck, such as Mech Warrior (including Dr. Boom, Mad Genius) this card is best reserved for Archivist Elysiana. Here we can play one of our two Bog Sloshers, either for our Barista or for any other card that may seem useful. If possible, we want to reserve the other Bog for our Shudderwock. 

Late/end stage (8-10 mana crystals)

This is our strongest point, and where we want to immediately and as soon as possible play Hagatha the Witch, as we want all that extra value, a little board clear and 5 juicy armor points. Also, this is where we unleash, if enough fueled, our divine Shudderwock. If correctly played, and at the right time, our victory should almost be ensured. Be wary that you may only play this card when considering it as an utmost important factor to allow us to survive or play a lethal. Playing Wocky when our hand is flooded or when it is not necessary is a huge risk and could make us lose the game, as all of our deck is centered around it. Here we can also play the other Bog Slosher, which ideally would be for our Shudderwock, but any other useful card may come into play.

Of course, we still have a ray of light if things seem against us; that's why we have Archivist Elysiana, for emergency situations where our Shudderwock didn't work, we still don't feel like playing it or when we have run out of cards (specially when against a heavy control deck). 

"My curse on you!"

Hope you like and understand the deck and its guide, and I will happily accept any critics, suggestions and complaints regarding them. 

Happy climbing!