Where can I find something suitably grisly?

Solution 1:

Give the ghost the Sated Hungry Charm you used to save Willow Blue.

1. Go to the first floor and pickup the Hungry Charm.
2. Go through the right door and use the Hungry Charm on the fishtank on the right side. (received Fed Hungry Charm)
3. Go through the right door, then the upper left door, and use the Fed Hungry Charm on the fish tank. (received Sated Hungry Charm).
4. Return to the dance hall on the ground floor behind the bar.
5. Light the candle to see the ghosts.
6. Wait for the ghost to pickpocket Aurum Runes at 5:30.
7. Talk to the pickpocket ghost to trade the Sated Hungry Charm for Aurum Runes’ invitation.