The Beast is at it's core quit similar to The Deck, but it has one very big difference in the form of a combo element. First of all The Beast uses the same control package as The Deck in the form of 3 to 4 each of Counterspell, Swords to Plowshares and Disenchant. The Beast also utilizes a big part of the restricted list by splashing all colors, exactly like The Deck. This of course also means that the mana base is exactly as greedy, if not more, because of the higher count of black cards in this deck.

The big difference is that The Beast cuts some of the "non essential" cards to make room for 4 Guardian Beast and a couple of Transmute Artifact. This changes the decks plan a bit as it can "combo off" either early or to lock up the late game. The plan is simply to survive long enough to be able to set up a "lock" with Guardian Beast and Chaos Orb as that means you can destroy one permanent each turn.

After that winning should be rudimentary as long as you hit your flips.