Inside the Titanic Bivalve Shell

d12
1. Miniature civilization of the intelligent lobsters, towers of carefully manipulated coral, cultivated fields of sea vegetation feed schools of domesticated fish, majestic compost heap where dead fish ferment subtly, security provided by mercenary squid w/polychromatic signal inks, vast bloated lobster queen lords over domain from spiral-shell tower
2. Subdivided into dungeonesque rooms, halls, corridors by aqua-dwarfs as depository for wealth, strong force of shock troopers on permanent watch on site, interior loaded w/deadly traps
3. Refurbished into merman dance hall complete with angler fish light show, variety of psycho-active toxins delivered via specialized stingray w/hypodermic barbs, strange sub-aqueous music provided by sea hag who plays trained puffer fish array
4. Lair of the amphibious dragon w/agoraphobia and his shipwreck collection arranged in tidy display
5. Vast swarms of harpoon-launching crab species warring w/giant scavenger sea-worms over rotting remains of titanic clam god, former occupant of shell, killed by rival deity after boasting of invulnerability, the more god-flesh they eat, the smarter they get
6. Coliseum seating installed, now active sea monster arena, operated by tribe of mermen ruled by money-hungry sea hag building expensive lair in surface wilderness area
7. Secret headquarters of wizard w/ring of kraken control, full of the monsters feeding, resting, awaiting orders, impressive houseboat in air pocket at top of shell, successful extortion racket along trade routes
8. Parliament of the Sea Demons meets here fortnightly, enacts legislation pertaining to inter-sea-faction trade, edicts enforced by extremely powerful Deep Fiend marshals, sea peoples lives in fear of surprise inspections, new and innovative taxes, impressment into armies of evil
9. Arcane bubble inside houses lair of mighty Sorcerer/Pirate Lord and crew in possession of U-boat stolen from 20th century earth
10. Heaped wreckage from entire ancient human city thought merely washed away by tsunami but actually dragged under by now-dead and decayed gigantic mollusk under orders from some forgotten god, golden treasures/other artifacts scattered about, thousands of bitter ghosts impotently dig through rubble for lost loved ones
11. Sea-god's home-away-from-home/swinging bachelor pad, usually occupied by variously hideous slacker demigods still living off the old man's largess
12. Colossal pseudopod of quite-alive occupant poised to instantly render any and all would-be invaders into hash