So in a few days I'll be running a one shot I've written up for my regulars but it's here I've been really trying to wow them. For instance, in private messages I asked them all one dark secret their characters have, why? The main antagonist of this one shot is a giant, hyper-intelligent bat, what's more is its psychic.

In what I'm hoping will be a particularly tense encounter the giant bat is listening out for them in a cave, taunting them by revealing its psychic powers, manifesting in spilling all their dark secrets.

As fun as that should be I want to end it with a bang and so I thought once the party kills the beast he could, in his dying breaths, tell them their future. Now my problem is I have no idea how I'd do that. My only idea would be to leave it vague, like "I see nothing but death in your future", which for the average dnd player is like saying I see bark on a tree.

So does anyone know how I could run this? Has anyone ever ran something like this and have some pointers? I'd be more than appreciative for any and all advice.