Underseas under the oceans, pools of black water with in some places only a few yorts (inches) clearance from water to ceiling, and it other places several yorts (miles) clearance. I think I may run with it. I am picturing cave sloths hanging from the ceiling, making constantly moving constellations with pertified snot dwellings built into the walls much like pueblo indian dwelling. Once I pencil it down to get my ideas straight, you may be getting another flood of submittals on the MOUES site.
Sorry if this is a little disjointed, i ripped it out of another post to keep the campaign cartographer hopefully on track. I started asking about underseas there and liked the idea enough to write way too much. No I still need to decide if this mostly aquatic area will be under a land mass or under the oceans. If it is under the ocean I can play with the dripping ceiling of the caves, and a religion based on keeping the sky from falling.
It will definitely cross under the oceans there will definitely be submerged oceans, but it won’t all be one or the other.
I think the first MOUES living Campaign module will be trying to find an Underwhere passage beneath the oceans big enough for Slog Schooners to navigate – rumored to have been discovered by Greta Anhil (The Anhil Passage).
Another thing you may want to play with is the Gawd Bladder. It’s sort of like a gigantic water balloon. On the surface it’s a lake, but the bottom of it is a mass of slimy membranes (probably bacteria or fungus, but I’ll find a more fun way to describe it in Holy Crap). The bottom of it protrudes into the Underwhere, so when you look at it from underneath it’s an enormous bloated sack hanging from the ceiling.
You may want to have smaller versions of that (or use the membranic fungi) in other places, such as beneath the Big Drink.