I bought a couple mushrooms and a few days later I noticed this small coral had hitchhiked its way into my tank. I assume it’s a coral but if anyone knows what this is let me know. I thought it was dead at first but I placed it in the tank and a couple days later noticed it started to open up a bit. Very small you can see the size comparison to the Duncan right behind it. I would say it’s no larger than a thumb tack. Any thoughts?