So, a player brought me this question, and I feel reasonably confident that I've got it but I want to be sure that I've accounted for everything.
First:
Massacre Girl has a trigger embedded within her ETB trigger. 603.12 (quoted below) describes reflexive triggers… Which, it appears, this
isn't. Her second trigger, “(w)henever a creature dies this turn…”, doesn't trigger based on an action taken during resolution of her ETB; it doesn't match either pattern described below. Instead, it simply creates delayed triggered abilities that sit and wait, watching for creatures to die later in that turn. This difference is largely semantic except that reflexive triggers “look back at conditions earlier in the resolution (of the ability that creates them)”, and this trigger doesn't do that (not that that's relevant in this case, creatures can't die
during this ETB, but possibly relevant for future cards with this template).
Second: If I control
Yarok, the Desecrated and cast Massacre Girl, then the additional ETB trigger created here will also include the embedded delayed trigger. So, all other creatures will get -1/-1, and anything that dies as a result will cause the delayed trigger to go off. If nothing does (or if we resolve all that), then the second instance of the ETB will resolve, give everything else -1/-1 again, and from that point on, any creatures that die will cause two -1/-1 delayed triggers to be put on the stack. So, with only a Yarok and a 2/2 Bear on board, if I cast Massacre Girl, the 2/2 Bear will die, and Yarok will end up with a total of -4/-4. And this interaction would be the exact same if Yarok was replaced with a
Strionic Resonator (choosing, of course, to copy the ETB and not the delayed trigger).
Was all of that correct?
Originally posted by Comp. Rules:
603.12: A resolving spell or ability may allow or instruct a player to take an action and create a triggered ability that triggers “when (a player) (does or doesn't)” take that action or “when (something happens) this way.” These reflexive triggered abilities follow the rules for delayed triggered abilities (see rule 603.7), except that they’re checked immediately after being created and trigger based on whether or not the trigger event occurred earlier during the resolution of the spell or ability that created them.
Edited Beau (Aug. 3, 2019 11:37:57 PM)