Tooth Decay: zombies that die
At first glance, it's just a zombie build, but there's so much synergy at play over dying creatures and their mechanics that the zombie aspect is purely incidental.
Obviously Gravecrawler is the boss of this build, as he dies and resurrects himself, on top of being just a wicked 2/1 beater. But combine him with essentially any other aspect of the deck and the whole thing explodes.
The inspiration for the build was the wildly undervalued Ghoulish Procession, which does everything this deck wants and more. Firstly, it triggers when A creature dies, not just one of yours. Secondly, it spawns 2/2 beaters that aren't a big threat on their own, but overlayed with the rest of the build mean a reliable 2 damage a turn. Thirdly, since they die to decayed anyway, they are PERFECT fodder for all your 'die' mechanics, such as your 6 sac spells, Carrion Feeder, and Undead Augur. Fourthly, since the tokens are zombies, they trigger all your 'when a zombie does X' stuff, which is a good portion of the deck. They work perfectly with Gravecrawler, Champion of the Perished, Undead Augur, and Wayward Servant.
The other good thing about this build is that it can survive nukes and grave hate better than you'd expect. Obviously neither is preferable, but if push comes to shove, you still get tokens to recover from nukes, can sac off your stuff for card advantage, and can always Gravecrawler your way back into the game. Grave hate really only targets the Crawler in this build, as the deck can run perfectly fine without him, even if it goes into overdrive with him, which makes it a minor bummer.
For the same reasons as above, traditional spot removal does next to nothing in this build, and most control cards are either dead draws outright or only target a small number of cards in the build at best.
Against other fast critter decks, the zombies either go wider or over the top (in theory) of most other critter builds. They won't win head to head interactions, but they spawn and grow so quickly that you can (in theory) out race Boros energy, for example. And against decks that want to ramp into something big, this deck smiles and goes wide as can be then swims right around the big drop.
Or, at least that's the working theory.