| It's hard to tell with out a picture, but I suspect the "creature" you saw was one of the various "pods" that you acquire with liverock. They are mostly harmless. Mantis shrinp have a very distinctve shape, and once you see one, even in pictures, you are not likely to forget it.
Quite a few things make clicking noises at night. When you say you found half a hermit crab, I suspect you had a hermit that molted, and you found the old shell. With hermit crabs you'll only find the front half when they molt. They have no shell overy the rear half and that's why they live in empty snail shells. Also when crabs molt, they are vullernable. Untill the new shell hardens, they will try to hide. It is possible something went after the hermit durring it's molting.
For now, I'd just keep an eye on things, and see what happens. |