I recently wrapped the Mountain of the Mad Marquis, an eight session delve into one of my dungeon23 projects. At the end of the last session, when the players returned to the bottom floor to loot the aftermath of the final fight, the random encounter table spat out a single Drow riding a Tuatara. With their consumable resources exhausted, their pockets filled with other treasure, and the NPC's capabilities unknown, the players elected not to challenge her for the haul. That's the origin story of Angrboda the NPC Cave Elf, who rocketed up to Level 4 off the loot, and her trusty steed Pythia.
Goblin Punch just made a cool post about ways to apply time pressure to dungeon exploration without having to track individual torch burn rates. One of his suggestions is to shrink the value of unclaimed treasure in the dungeon each time the players go back to the surface. There are a couple ways to explain this, such as dungeon creatures carrying off the treasure, or the dungeon being a metaphysically hostile place that didn't want you to take the money out of it. I prefer the former, since it's something real the players can interact with if they realize what's happening and plan around it. DCSS had monsters like this, slimes that would hoover up items and dissolve them if you were slow exploring. They'd eat anything you left behind in the Slime Pits once you killed the boss and opened up the vault.
Let's use Angrboda as our first Cleaner, to explain where all the money went.














