I made a pretty big gamble in my Masks game tonight and I'm pleased to say my players loved it.
So one of my players plays Cypher, the Protégée to a mentor who is a detective superhero whose archnemesis is the Spider, a faceless villain behind a crime syndicate (her mentor is essentially a cop but that only makes her more fun to rebel against)
As a GM, the Spider was one of the first NPCs I created. The players only ever interacted with them through their underlings (a coterie of bug themed villains I'm pretty proud of). I've had plans to introduce the Spider under their civilian identity for a couple sessions now, but the opportunity never came up. To be clear, the investigation into who the Spider is isn't core to the campaign, they're mostly a background villain I use as an excuse to make the mentor have demands of Cypher.
Toight, while interacting with one of these underlings (or former underlying, it's complicated) Cypher's player decided to trigger her moment of truth, which are essentially trump cards that can be used once or twice per campaign, give the players a ton narrative control and make a playbook's core conflict shine. The Protégée is as follows:
The moment that you show who you really are: your mentor, or something different. You can do whatever your mentor could do and more. You can do the incredible, even the things they always failed to accomplish. Of course, they’re not going to see you the same way, no matter which path you choose…
As a result, by rejecting the cold distance and superiority of her mentor and chosing to show understanding, Cypher uncovered a crucial clue that leads her to discovering who the Spider is, a perfect interpretation of "the things they always failed to accomplish". But this left me in an awkward position since I hadn't yet introduced the Spider's civilian identity, it would've been underwhelming to say "he's this guy you've only heard of couple times and never met" so I just turned it back on my player and asked her to tell me who it was.
What followed was a great moment where everyone pitched cool ideas about which NPC could've been the Spider all along, everyone bouncing ideas to justify their motives etc, while giving Cypher's player final say. We finished the session without a clear answer but several ideas I'm really excited about, Cypher's player will give her final answer next session and no one was bummed by not getting a "true" answer (which I still offered btw)