Back when I had made the modular river for Song of Blades and Heroes skirmishes, I had cut a bunch of other pieces of MDF in various shapes. The plan was to use them for things like swampy ground and ponds. The largest of them was for a small lake.
I pulled that out and decided it was big enough for the pool in front of the entrance to Moria. First I placed the board on a piece of foam core.
(The grid in background are 1" squares from a Chessex mat)
Next I traced it. Since the foam core was black I used a white correction fluid pen.
Once the trace was dry, I cut it out with an Xacto knife.
I traced an internal line about 1" from the edge of the foam core and cut that out.
The resulting ring will be the "shore" of the lake. I glued it down and put a couple heavy books on it to hold it flat while it dried.
The next phase will be to shape and bevel the edges a little, as well as fill them with some spackling or pumice to make them seem more natural. When that's done, I'll paint it.
While that was drying, I took a first stab at a greenstuff Watcher tentacle. It's about 3 1/2" long, rolled around some copper wire. I made the sucker marks with the end of a detail brush handle and the point of a toothpick. It's pretty basic, but I think I'm on the right track. I may have to paint it up before I can decide.