Hearthpwn

This deck uses the Shark Spirit (with Cold Blood) for massive draw for aggro decks - yeah, aggro decks :D.

Explanation (it's a little long :D): This deck uses board control, pirates, weapons and battlecries together, which is a little too much. but it kind of meshes together through all the pirates with battlecries and weapon buffs.

Cannon Barragecan be used as a finisher, or really whenever, because of its no negative outcome (like Leeroy). The Pirates really help out, and a simple Sharkfin Fan + weapon attack with Cannon Barrage deals 10 damage! Plus another 10 or so with leftover pirates in hand.

Here comes the fun stuff.

Spirit of the Shark has quite a powerful ability. With it, you can pull of some incredible combos. Some examples are triggering off a Vancleef twice, or double Faldorei. but note that with this card you can also get some insane card draw! With Elven Minstrel, Face Collector and Ravencaller (because I want to be special :D) you can get yourself some neat hands for your Vancleef and other cards.

Mulligan:

Against control, mulligan for your 2 mana removals. They (should, theorycraft) help fight Tar Creeper, and after that you can draw into Vanish or Fan of Knives. Still die though.

Against aggro, draw for Fan of Knives and Betrayal.