Yogg-Saron's Anomalies could only be contained within Battlegrounds for so long. Yogg-Saron's faithful servant, Cho’gall, is coming in the Fall of Ulduar to unleash Anomalies on Standard, Wild, Twist, and Arena, too!
Cho’gall “corrupts” the game with a random Anomaly. The Anomaly effect is revealed prior to your mulligan and activates after the mulligan, but before the first turn is taken. At launch, there will be 20 Anomalies, each with an equal chance of corrupting the game
In addition to Cho’gall’s effect, Anomalies will be active in all games for the first week after the launch of Patch 27.4. After that one week period, Anomalies will then be active in 25% of games until Patch 28.0. If you or your opponent (or both of you) have Cho’gall in your decks during these event periods, there’s a chance your game will be corrupted by two Anomalies at once!
Should be a fun week!