Building 10 rooms

BOG WEED:        PLANT
PYRAMID PHOENIX: MONSTER
THUNDER OOZE: VERMIN
HUMMING ELF: HUMANOID
STAR GORGON: BOSS
STAR WOLF: CRITTER

I--A--B
| |
J--C--D--E--F
| | | |
G--H
Room A.
Long flight of marble stairs painted black and white like piano keys. Stepping on wrong stairs flattens them into slide, makes climbing extremely difficult, getting down fun. Somebody in room H knows secret pattern or it's hidden in mosaic on walls. Anyone who's a musician gets a bonus to working it out. You decide which side PCs start on.
Room B.
SIGHT: Cobwebs in every corner.
SOUND: Muffled voices from next room.
Staircase wraps around inner wall of well. One exit high up, one at water level. Water pitch black. PYRAMID PHOENIX that lives in well usually not hungry, can be roused to surface by ringing bell at very top of shaft.
Room C.
Single enormous BOG WEED growing up towards skylight in very top of room. THUNDER OOZE nesting in roots.
Room D.
BRODOMPA the STINKING SALESMAN looking for girl/boy/personfriend, who they think is being held captive by HUMMING ELFS. Actually came with them willingly to get away from BRODOMPA the STINKING SALESMAN, now rethinking it, dungeon life losing sense of mystery and grandeur. Still hates BRODOMPA the STINKING SALESMAN though. Is in room H.
Room E.
SIGHT: Room is part of ancient mansion, walls are rotting wood.
Narrow bridge across swiftly-rushing underground river. Anyone who falls in will be carried out of dungeon, take bashing damage from rocks. HUMMING ELF ambush party clinging to underside of bridge and/or ceiling, will attack halfway across. Some kind of perception check to spot.
Room F.
SIGHT: Fetishes of bone and feathers dangle from the ceiling.
ORDOO the KIND SCHOLAR, playing the flute. Has no idea they're in a dungeon. Can see everything around them perfectly clearly, just refuses to believe it's a dungeon. Will confabulate other things it could be. Flute not magical unless you desperately need it to be.
Room G.
Looks like three-way intersection. One exit actually trap, leads to immediate dead end and floor collapse. Then HUMMING ELFs come in and start poking you w/ sticks.
Room H.
SMELL: Faint breeze. Hard to tell where from, seems to change directions.
SOUND: Creepy singing, like every nursery rhyme in every horror movie ever.
High ledge w/ two entrances that looks out over vast lake of lava. One HUMMING ELF peacefully fishing w/ brass rod, wire, hook. If left alone long enough he will catch something. 50% chance of hungry lava fish, 50% chance of lava treasure.
Room I.
Hideout for rebellious HUMMING ELFs, unwilling to recognize authority of STAR GORGON, want to establish tiny republic in forgotten dungeon crevice.
Room J.
SIGHT: The roots of an ancient tree emerge from the roof.
Formerly a wizard's study. Now a breeding pair of STAR WOLFs has made a nest of the spellbooks, which reveal interesting magical snippets if closely examined. Torn-up pages, gummed back together, may have produced odd new spells.