Building 10 rooms

SLIME BRAMBLE:  PLANT
HALF-ELEMENTAL: MONSTER
CELESTIAL CRAB: VERMIN
MERCURY KOBOLD: HUMANOID
ROYAL GOLEM: BOSS
SPECTRAL HOUND: CRITTER

J--D--F
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A--B
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G--C--E--H
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I
Room A.
Bubbling lake of mildly corrosive alkaline goo must be navigated via stepping stones. CELESTIAL CRAB hidden in goo, obviously. Harmless until you get any blood in the goo, then will go into feeding frenzy.
Room B.
Salt lick. Vein of salt (somehow) in wall of cave, SPECTRAL HOUNDs lapping at it. If you bring salt to other parts of cave the SPECTRAL HOUNDs there will lick it out of your hands and it will be adorable.
Room C.
Room shaped like inside of tetrahedron. Anyone standing in etched circle in room's centre teleported to random other room of dungeon. Can be controlled by fetching tetrahedronal crystal in room G, will grant access to secret treasure chamber w/ no doors leading to it. Someone has to stay behind to teleport you out again.
Room D.
Panicky MERCURY KOBOLD wearing obviously-stolen GAUNTLET OF WISHES caught at fork in road, not sure which way to go. In one round FELWEND the NERVOUS EMPRESS, conspicuously missing GAUNTLET OF WISHES, will emerge on scene and demand it back.
Room E.
SOUND: Crunch of footsteps on sand.
HALF-ELEMENTAL asleep in centre of irregular room, can only be squeezed round w/ difficulty.
Room F.
SOUND: Whistling of underworld wind from cracks in wall.
Bedchamber of three, four MERCURY KOBOLDs. Sodden and filthy. Careful inspection of damp rags that serve as bedding will reveal a(n) CLOWN'S NOSE in surprisingly good condition, but forces save against filth fever.
Room G.
SMELL: Old people and medicine.
SOUND: Hiss of steam escaping through cracks in floor.
Bunch of MERCURY KOBOLDs quivering in fear as you approach. HALF-ELEMENTAL followed you in, is directly behind you.
Room H.
ROYAL GOLEM bedchamber. Four-poster bed, priceless paintings kidnapped from world are hung on walls and artistically befouled. Fairy kept in cage as singing nightlight begs release, claims to be able to grant wishes, can't. Golden key to cage discarded in room B, ROYAL GOLEM concluded they will never need it. Cage highly portable, otherwise unbreakable.
Room I.
Map room. Globes, nautical charts, atlases, blueprints, guidebooks. ROYAL GOLEM studying X-marked plan of faraway island, so enthralled that it has difficulty noticing PCs. Exquisite rug on room's floor seems like abstract pattern, careful study reveals it to be map of dungeon itself.
Room J.
SIGHT: Walls are sandstone, gritty when you touch them.
SMELL: Spilt beer accumulated over decades.
Actual dungeon, exists to hold prisoners. Guarded by pair of MERCURY KOBOLDs, one sleepy, one watchful. They are siblings. Couple of human captives in pitiful condition, starving in cells. One is ZERKLEY the MOROSE ASTRONOMER.