So the new Witchwood set came out for Hearthstone and one card stands out over all the others. Shudderwock. It is essentially the spiritual successor to Yogg-Saron a card that would cast a random spell for every spell you've cast in a game. The main difference between the two is that Shudderwock doesn't cast random battlecries, it casts the exact battlecries you've played in the game but gives random targets. So anything without a target works exactly as it normally would.
Because of the way the Shudderwock mechanic works you can almost create an infinite loop once played with devastating effects. I'm guessing that this isn't working exactly as the design team intended and could possibly end up getting changed. It's quite unfortunate since Shaman has been the worst class for a while in Hearthstone and I'm not even sure the Shudderwock deck is currently one of the best out there.
As the meta settles in we will see if Shudderwock has any longevity or if it's just a temporary novelty.