I envision some Runequest-style demonologists and a cult or three for the big hopping toad idol at the top. Came back to the whole thing and inked the first layer of walls after reading some of the stuff in the unofficial Fiend Folio II that +Greg Gorgonmilk posted onto the G+ thread
Lots of traps and maybe a few secret passages. Gateway drugs into demon-toad worship and the bodies of a few dozen innocents. Mugwumps, doelms, and bullywugs. Flooded passages (haven't decided which they ought to be, yet)
This is the basic version but maybe I'll do up a thing like Dyson does with all the hatching. It's soothing and a stress thing and good for goldbricking at meetings. Or while waiting for clients to arrive or fill out paperwork. Writing the odd dissonant hymn or dirge to a toad demon while waiting for the coffee to brew
If I had used the scanner I could have cleaned up some of the pencil lines but then I'd have had to clean the back desk off and... Well, I will work it out later.