Even if you're only remotely up-to-date with Blizzard's digital card game, you only need one guess. Yes, the god of random himself, Yogg-Saron, will be getting a significant tweak before the Hearthstone World Championship kicks off later this month.
The update hasn't gone live yet, but when it does, Yogg-Saron's ability will cease if the card itself is removed in some fashion while its entering-play effect occurs. This includes silencing effects.
Yogg however wasn't the only card targeted by Blizzard. The developer put together some helpful before-and-after comparisons so you can see precisely what's what:
The Shaman changes aren't unexpected, with the class currently dominating the competitive scene. The mana increase to Call of the Wild feels like an olive branch to the community more than anything, while the tweaks to Charge and Execute should see a decrease in aggressive and "one-turn-kill" Warrior decks.
With the Hearthstone World Championship starting on October 26, the developer didn't really have much time to roll out the changes, while leaving enough of a buffer in case something goes immensely pear-shaped as a result.
Upcoming Balance Changes - Update 6.1.3 [Battle.net]