Saheeli, Filigree Master/Blackbalde Reforged Bug
I was playing sealed on PC. I used Saheeli, Filigree Master's +1 and tapped Blackblade Reforged. I was instantly dealt 13 damage to my 12 life and the game ended. Nothing triggered, I just took damage and the game ended. Blackblade Reforged was giving +13/+13 at the time. I didn't get a screenshot of the board because it just instantly jumped to the defeat screen.