Grymvald Gazetteer always has a good find regarding history and archaeology. His recent blog entry on a discovery of a small cache of Roman and Iron Age coins in a cave in north-central England is good imagination fuel. Although the cache is 'only' 26 coins, it has potential for being a good lead-in or adventure seed.
I'm all about the instant 'found' dungeon. But closer observation of the 'Cave' yields it to be merely a stone arch.
No worries, the arch may contain a hidden side cavern. Dyson probably has something I can re-skin...
Ahem, "Reynard's Cave"...
Although the stone arch known Reynard's Cave is perched along a main trade route, it is typically shunned by passerby. A mysterious highwayman, nicknamed Reynard, frequents these parts. Locals say that the arch was enchanted by the thief, such that he could disappear by simply running through it, as if he were transported to another place! A few brave souls who chanced to look in the arch say his bootprints disappeared, but noises and auras within the stone caused them to flee before investigating further.
Indistinct, threatening whispers are heard within the arch (as magic mouth). PCs may feel unease, if not outright fear. Those with strong enough will may note that the wall of the cave shows numerous runes and figures.
Characters may notice a recently covered area along one wall of the arch. A bit of digging will uncover a leather bag with 16 SP and 10 GP of varying mints and sources. While a few are local, many of the coins have come from a fallen empire or distant trade routes.
1. The entryway appears to be a stone wall and is obscured by a permanent illusion (as hallucinatory terrain) requiring disbelief, someone passing through, or some other methodology. This, of course, was Reynard's secret to his escapes. The entryway to the caves slopes downward, and is weakly enchanted with a continual light spell (radius 30').
2. The cavern opens to a large room - the floors are packed dirt, with slight drips on the walls. The light from the entryway barely reaches into this area. Small vermin tracks are visible throughout, many trailing off to the left where:
3. Stacked within this side-cave is the majority of Reynard's larger materiel takings - while his local reputation was great, his collection is rather mundane...
Among the items may be found the following:
2 flasks acid (20 gp )
2 flasks antitoxin (100 gp, reduces poison damage by 1/2)
10 Flasks of Oil (10 sp, 5 lb)
4 Flint and Steel (1 gp)
Large Chest, empty (30 gp)
Crate with 11 Bottles of Common Wine (11 sp, 4 lb)
1 Bottle of Fine Wine (10 gp, 4 lb)
Miner's Pick (3 gp, 10 lb)
Box of Sewing Needles (5 sp)
Small Magnet (10 gp, 1 lb)
Tent (10 gp, 20 lb)
10 Bags of Rare Spices (10 gp, 1 lb)
Sack of Wheat (5 sp, 50 lb) (rat-knawed and leaking)
4. The area is filled with broken crates and bags. There is nothing of value here. An immature Ankheg (3HD, AC 2/18, bite 1d8, acid spit 2xday 2d4 damage/save for 1/2) has tunneled in here and hides beneath the detritus. It has subsisted on rats, but is hungry and growing, and will attack any intruders. Its tunnel is too small and unstable for any PCs to pass through.
5. Reynard's chamber and library. Here Reynard (real name: Tyne Bluth) rested and lurked between raids, sorting his most valuable prizes, reading a few pilfered books. The room is furnished with a rough bed and table. On the table and in a box are 3d4 books, 2 will have value of 50 gp each to collectors. A high quality rapier in an ornate red-shellacked scabbard with a local noble's crest is stashed beneath the bed's mattress (100 gp) (This was owned by the son of a local duke, who hasn't admitted the loss of this heirloom to his father, and who will pay well for its quiet return). Buried under the floor beneath the table is a small chest (poison needle trapped lock, save or 2d6 dam) (80 gp, 240 sp, 3x9 gp agates) (The key is in one of Reynard's pockets, Area 6.).
Sitting on the table is an open bottle of wine and a half-full crystal goblet (12 gp). On the table sits a small metal (lead) chest. Within the chest is a small scarlet Ossifying Jelly* (3HD, AC7, Mv 3, dam 1d6, save or ossification of joints, followed by the organs (and death), over 1d4 hours, acid causes 2x damage, normal weapons cause 1 hp/hit)). It was being transported by a religious zealot on a mission to incapacitate a rival religious figure when Reynard relieved him of it. The jelly was in a torpor when Reynard was foolish enough to poke at it, but he began to feel its effects moments after slamming the lid of the chest back down.
6. A contorted, twisted body lies in the passageway. The body (Reynard's) appears to be partially mummified, his bones and joints seized and petrified. His face is permanently contorted in horror and pain. He appeared to be crawling into the depths of the cave when the final petrification overtook him. In his hand is a filigreed and gem-covered egg (500 gp, very fragile, a secret clasp on the egg opens to reveal a tiny golden carriage).
7. Arrayed in the back cave is an ancient temple space, with standing stones around a shallow lime-filled pool. The water glows dimly, but is otherwise unremarkable. The area is a shrine to the goddess Isset, a near-forgotten deity of discord and rebirth. Offering by sacrifice (i.e. destruction) of a sufficiently valuable item will grant a blessing by the goddess (including reversing the ooze damage). Many shattered gems, broken weapons and glassware, and damaged jewelry are scattered about. Although collection of fragments and slivers of jewelry will yield 4d50 GP worth of valuables, it will also earn the goddess' disdain (-1 to saves for 1d6 days for all in the party).
So there it is - a hidden mini-dungeon with a nasty hazard and hidden cure. And I live by random tables. Serendipitously, I rolled up both the ooze's vulnerability (acid) and acid flasks in the treasure trove...
Sometimes things just work out...
*Thanks to Richard LeBlanc's Blob Generator Table for assistance in creating the Jelly...