Doing the weekly event for 10/8 - Mormir x=7 Serra's Emissary seems to have frozen the game for me and my opponent, though a reset fixed it for me (my opponent was apparently locked out, since they did not take another action). I was not offered the option to choose a type, and Artifact was selected for me when my turn time ran out (I would guess this is because Artifact is first alphabetically). I just had the Mormir emblem item on the stack, and it never resolved until time forced it to my opponent.
Notably, I also had Queen Allenal of Ruadach, which meant I got a 1/1 at the same time as the Emissary since it was a token Emissary.