https://www.pcgamer.com/hearthstones-new-expansion-already-has-a-game-breaking-combo/

The theme of Hearthstone’s latest expansion is a dank, haunted forest, lingering outside the walls of the cursed city of Gilneas. However, with The Witchwood only a couple of hours old, it already appears that something spookier is haunting the Hearthstone community: a new degenerate one-turn-kill combo. This spectacular combo is the talk of the pro player scene, and to be honest, they're right to be afraid.

Here's how it works. The new Shaman legendary, Shudderwock, has a Battlecry effect that repeats every Battlecry you've played over the course of the game, but in a random order. Your goal is to build a very specific pool of Battlecries which, when played together by Shudderwock, are so potent that you can kill your opponent in one (or maybe two) turns. You do that by playing the following cards: