A Rumor of Dungeons

d12
1. Vast, yeti ghost-haunted cavern covered in obscene cave paintings allows access to Underworld via mystic doorway that must be constructed of enshrined cave bear skulls
2. Active ooze hive festers under the city, empties into nearby river/lake/sea, visited by famous sorcerer who departed atop perfectly obedient colossal pudding-steed
3. Death row convicts attempting escape tunnelled into unknown chamber, their dessicated corpses appeared on the courthouse steps at daybreak
4. Reasonably sane captain of the watch insists silver hatch appears beneath city wall only when in direct light of full moon, swears invisible things come out
5. Cult membership of the God of Plenty make fortnightly journey to underground complex in adjacent wilderness under the cover of night, never speak of it to outsiders
6. Unpleasant music emanates from farmer's recently dug well
7. Prince's pyramid project halted by lack of shipments from new quarry, trusted captain dispatched to investigate w/soldiery, not a peep
8. Sorcerer's griffin-borne aerial survey detects huge, ornately camouflaged mountain top chimney spewing forth weird gases
9. Rocket-shaped wizard's tower takes off, sub-surface floors left unattended, someone should at least strip the plumbing
10. Dragon moved in to proximate cavern not to plague the land in fulfillment of dire prophecy as is the prevailing wisdom, but rather to jealously guard secret entrance to antediluvian culture's treasure vaults
11. The Fetid Sewers of the Ancients drain into another world
12. War-gangs of ogres and mixed-humanoid lackeys loot frontier towns seemingly emboldened by smart attire, beautifully crafted garments/armor, chaotic evil chic, shields emblazoned with device of  the Tailor Below