This just appeared in my reef tank today. Haven't added anything in 3 weeks so not sure what it is. Looks to be a snail of sorts with the shape and style of foot. I looked up all kinds of nudibranch and didn't see anything like this. It obviously moves since it wasn't there this morning and when I got close to it, it seemed to flinch some but has been in the same spot for several hours now. Appears to be almost feathery in appearance. Greatly appreciate any help in identifying what this may be.