Hearthpwn

This deck is very aggressive, and it is performs very well in the current aggro-heavy meta by being more explosive than other aggro decks. It features powerful mech synergies, including the single best class-specific mech card in Metaltooth Leaper. And it brings along our good friend Undertaker for the ride.

The Undertaker Package

• Undertaker - the primary source of leukemia, melanoma, and mesothelioma
• Leper Gnome - guaranteed 2 face damage, also a 1 drop
• Mad Scientist + traps - Mad Scientist offers crazy amounts of tempo (and in my opinion, causes far more cancer than Undertaker. Mad Scientist is the guy injecting all his patients with cancer, and Undertaker just runs the hospital morgue, yet he gets all the blame) I only play 1 freezing and 1 snake trap, because I never want to draw them
• Deathrattle Mechs - Clockwork Gnome, Harvest Golem, Piloted Shredder - it's like the designers wanted Undertakers and mechs to be played together

The Mech Package

• Mechwarper - I shouldn't have to explain why this card is good
• Deathrattle Mechs - Gnome, Golem, Shredder - ditto
• Annoy-o-Tron - protects your more important guys, also very annoying
• Micro Machine - The idea is to have too many threats for your opponent to remove. This card attacks for 3, 5, 7, and demands an answer immediately. Between this, Undertaker, Mechwarper, Knife Juggler, and Jeeves, your opponent can't remove everything.
• Metaltooth Leaper - this guy is a house. If you can drop it and pump 2 or more guys, you will probably win the game
• Jeeves- usually draws you 2-3 cards around turn 5/6. It's obviously less good in the aggro mirror, but this card is a must vs. midrange and control. Oh, did you know it's also a mech?

Rounding out the deck

• Knife Juggler - another card that demands an answer or it will just dominate the board. Also combos with snake trap/UTH. Again, your opponent can't remove everything
• Ironbeak Owl - 1 silence to break past taunts / silence opposing threats
• Unleash the Hounds - Only running 1 because it is your only way of recovering the board against zoo and the hunter mirror, but it's bad against everything else. Try to save it to use with Knife Juggler when you're falling behind on board.
• Kill Command - Strictly a 1-of finisher to deal the final points of damage. You'll find a lot of times you won't have a beast on board to activate it. That's ok.
• Loatheb- seals the game when you have board dominance or are threatening lethal

Why no...?

• Webspinner - This deck does not utilize hunter's beast synergies. A 1-mana 1/1 is not impactful enough. You don't want a Core Hound clogging up your hand when you're trying to draw with Jeeves.
• Animal Companion - Does not synergize with Undertaker or mechs. This deck does not rely on beast synergies
• Mechanical Yeti - too slow, not a sticky minion, and there's a 1 in 7 chance that your opponent gets the taunt spare part and you lose the game
• Eaglehorn Bow - possibly could be included as a 1-of. I did not test this as I was having success without it.
• Savannah Highmane - 6 mana is just too slow for this deck. The curve basically ends at 4 with Loatheb being the only 5-drop. The goal is to empty your hand and refill with Jeeves.

Mulligan Priorities:

1. Undertaker, Mechwarper
2. Mad Scientist, 1-mana guys
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100000. Traps

Proof of legend:
http://imgur.com/a/0DmXB