I noticed this under my Hairy Mushroom's rock and i had originally thought it was the foot of the mushroom but i am starting to think it isnt. Any help would be greatly appreciated!
No im not sure where it came from. I just thought it was a nice piece at my LFS that had a giant hairy mushroom on it. Would the anemone harm anything?
If it were in my tank I would not remove it, but I would place that small rock where I could keep an eye on it. Remember they like the shaded, under hang type areas.