Start randomly rolling dice to totally freak them out

GM pro tip, *let the player come with the plot, they'll be so impress by the complex plot you came out with and so proud to have found-it, while actually you just said yes to their ideas*

Wait was this the minor character from that side quest all along? .....yes....it was now

Things get messy when the GM forgot about that minor NPC like *I'm going to see Elia ? Who ? but Elia, the fixer we saved from the Corpo guard, she said we'll always be welcome*

Barry blue jeans!

My favorite is when the players break out some custom item you have them thirty sessions ago and you have to figure out what it does on the fly. "Remember that potion you gave us? The one mysteriously labelled 'Brew 36'? I just drank it, what happens??"

It's like that Batman episode where the Penguin left a "clue" for Batman with a bug in it and then used Batman's speculation on what it could mean to plot his next crime.

i have a binder of random lists. it's perfect for scenarios like this.

'how much is your passive perception again?' rolls dice, just nods

Or if you really want to scare them, Charisma save.

The Green Hornet too. Using speculations from a journalist to make plans.

I treat the game as both a game and a collaborative writing thing; if the players come up with a better plot than I originally had planned, my plans will be altered.

This happened last game sesh! I was ready for them to be confronted by my badass NPC only to be reminded they had already befriended him several months ago.