Having played a fair deal of live Magic, specifically Theros Block Limited, I wanted to do a series of blogs on various Missed Triggers that may be confusing to players and judges alike. First up is Kragma Butcher, one of my favorite red commons in the block.
"Whenever Kragma Butcher becomes untapped, it gets +2/+0 until end of turn."
The ability triggers during the untap step and goes on the stack at the first opportunity in the upkeep step. Rargh! 4/3 Butcher ready to go to Brown Town.
Let's say I attacked with Kragma Butcher last turn for two. Now on my turn I untap it, draw my card, play a land, and attack again. My opponent has a Karametra's Acolyte (1/4) and decides to block since I said nothing about the trigger.
Is it missed?
The answer is... not yet. Although the ability goes on the stack during my upkeep, because it has no effect on the visible game state, I am not required to demonstrate awareness of the trigger at that time. I just have to do so when it becomes relevant to the game. In the case of Kragma Butcher's +2/+0 trigger, that probably means when it attacks and deals combat damage. Going back to the above scenario, I can do this by saying "Okay, go to damage. Your Karametra's Acolyte is dead." The same holds true if the Butcher goes unblocked. If I say "Take four," I've demonstrated awareness that the trigger happened.
How then do we know if the trigger is missed? If I let the Karametra's Acolyte stay on the battlefield after combat, or I tell my opponent to take two damage. The baseline assumption with triggers is that they did happen unless something happens that would indicate otherwise, in this case a Kragma Butcher that untapped only dealing two damage in combat.
As the opponent, how can you tell if the trigger is missed or not before damage? How can you figure out if you can safely block with your Karametra's Acolyte or not? You ask. you probably don't want to ask "Did you remember the trigger?" because that's a bit of a giveaway. A simple "How big is that?" should suffice. If they say 2/3, go ahead and block.