ID Please

[2pts]

Hello all.

This was in my corner overflow for about 8 months, no idea where it came from but I left it alone. Recently it un-attached and got sucked down the over flow ending up in my sump.

I fished it out and put it into my display, thinking it was some kind of aptasia type thing that my copperband butterfly might munch on it (he polished off hundreds in about a week, now trying to grow aptasia in a 3 gallon).