Hearthpwn

This deck helped me beat Heroic Lord Slitherspear on the second try. The main goal of the deck is to use Animated Armor and your freezing cards such as Ice Lance, Frost Nova, and other cards to stall out Lord Slitherspear until you can either kill him with minion damage or get the cheese strat out.

What is the cheese strat, you ask? Playing Kel'Thuzad with Annoy-o-Tron or Mirror Image. The Blizzard AI will not attack a taunt if there is a Kel'Thuzad behind it, so you are pretty much safe to hit his face.

Animated Armor is your best stalling method. Other decklists online only include Animated Armor minions in hopes of your minions being able to deal all the damage, but if that doesn't happen, you have an alt win con which is your cheese strat. 

You can still win with stalling and minions because I added in an Arcane Golem for burst, because I often found myself missing 2-3 damage and that ended up causing me to lose the game. 

If you find that this isn't enough stalling, then you can tech in a Blizzard.

Spellbreaker is used instead of Ironbeak Owl because it is a solid 4/3 body that might be used for trading or hitting face.

Watch out for Slithering Archer! He runs 3 of them, so make sure that you don't play your mirror images into them. His usual turn 1 play is hero power + coin Slithering Archer. 

Hard mulligan for Animated Armor and Annoy-o-Tron. If you don't get Animated Armor in the first few turns, then concede and try again. 

Once you get Animated Armor out, ALWAYS attack his face with it, you need to kill him ASAP. He will usually deal around 7-8 damage per turn to you, so you will want to play Antique Healbot and Ice Barrier ONLY AFTER you play your armor, as they will buy you one turn each. Frost Nova's can be used more liberally, but you should try to use them to buy you extra turns once you already have the armor up.

His deck also runs 2x Curse of Rafaam, so make sure that you stay above 4 health, or else he can burst you down through your Ice Barrier or Ice Block

I don't run Deathlord because it kept pulling Icehowl from his deck and he would charge into my Animated Armor, causing me to lose the game more than once. 

The AI should never attack your Animated Armor with his Nagas, but be warned that he will start killing Animated Armor's once you get him down into lethal range, so try not to get too low that he can kill you on the turn that he trades with the Animated Armors. Good luck!