Turbo C'Thun Druid

Malygos Druid may be fun for a while, but it requires more setup than this deck, where we use C'Thun, the Shattered in tandem with Flobbidinous Floop for a 60 damage OTK. You can get there pretty fast, because you have tons of card draw and ramp. While the combo is normally impossible, that is why we are running Jungle Giants to play Barnabus the Stomper and reduce Cost of C'Thun or Floop to (0). You may use Emperor Thaurissan, but I bet my version is a bit more reliable, because you get C'Thun for cheap much faster and more reliably - just play one of his pieces and Barnabus in one turn.

To complete the Quest, we can either summon five, predetermined 5-Attack minions (Cursed Disciple, Forest Warden Omu) or buff cards like Anubisath Defender with Embiggen.

Depending on your draws, you may use Juicy Psychmelon to tutor C'Thun and instead opt for a 0-Cost Floop, which also works. But you will mostly reduce Cost of C'Thun himself, since he can be safely dropped to cheap costs.