[2022] Deck-breaking bug is going to be live on Arena for the event this weekend, and is going to make playing UR or Jeskai a MASSIVE disadvantage.

Hey everyone. We posted this in another thread on this issue, but also posting here for visibility! An update here on this issue - which thankfully isn't as impactful as we thought. After further review and testing, we found that this initial bug report didn't operate the way we initially indicated. It should be fixed with the release of Alchemy: Kamigawa, but it will still impact this weekend's event. Going into further detail below:

Smashing and Opus work as expected to remaining targets in the normal case where one or more of that spell's targets for damage are made illegal via hexproof/sacrifice/protection (and one or more legal targets remain). Instead, Smashing/Opus will not do damage only when something above it on the stack has a target that fizzles. So for example, Showdown of the Skalds Chapter 2 or 3: Say the Smashing player controls Showdown, and they cast Smashing. Showdown triggers and targets one of the Smashing player's creatures with +1/+1. If that target is made illegal in response, only then will Smashing deal no damage.