MiriDew

I was in blackreach just now and found a black with moss or something green.... thing. A hollow.. pod? I hit it and it broke open, and pieces flew everywhere. It was empty It is along the waters edge, a little bit underwater, and next to a bridge, ill include a locational reference photo of the bridge and background shrooms if anyone else wants a look see. What in Bethesda's name is it? I cant find any reference to anything like it anywhere in the web and my boyfriend who is super mr skyrim has absolutely no idea. *I have hearthfire and dawnguard installed, and it is on xbox 360. Please help, im so confused. **Please excuse bad photos, my tv and camera dont work great together so everything turns neon blue.