ID object on Zoa

[submersible]

I've had this colony for some time now, and just noticed this object on it.
Any idea what it could be?

Thanks

http://img827.imageshack.us/img827/5048/object.jpg

http://img267.imageshack.us/img267/8509/object2.jpg

[mutateddogbone]

looks like sundial snails, predator of zoas. remove the colony immediately and dip in coral dip or set in freshwater for a few minutes. make sure to remove all snails

here is a good link http://www.worldwidereefers.com/forums/showthread.php?4768-Hitchhiker-id-guide

[submersible]

Thanks. These things creep me out for some reason.http://img193.imageshack.us/img193/456/pukea.gif
Just removed 2, and another without any markings. They had a stretchy spider-like string attached to the coral.

http://img695.imageshack.us/img695/7594/img1054e.jpg

http://img843.imageshack.us/img843/4820/img1056mf.jpg

http://img16.imageshack.us/img16/2220/img1058ss.jpg

[zma21]

As a zoo lover and noob collector, I just cringed. Yeek.