Matt Tabak:

Okay, I’m my defense, the House is scary and it was hard to focus, but unfortunately there’s something in the #MTGDuskmourn mechanics article that needs to be corrected. Let’s talk copies of Rooms. If you copy a Room spell on the stack, you get the same choice as the…

original spell. The same door unlocks, and the token’s “When you unlock this door” ability will trigger (if it has one). If you create a token that’s a copy of a Room on the battlefield, the new token has both doors locked. Same if something enters as a copy of a Room.

It gets more complex if a permanent already on the battlefield becomes a copy of a Room. In that case, consider whether the original permanent’s left/right doors were already unlocked. In most cases, this means it was a Room. If so, those doors will be unlocked on the new Room.

If something that was never a Room becomes a copy of a Room, both doors will be locked. As always, you can open a locked door as a sorcery by paying that door’s mana cost. #WotCstaff

The shorthand in the mechanics article has been deleted, and we’ll leave the details for the Release Notes. Sorry about that. Back to the previews!