Never seen anything like this one..

[Kraz]

Any ideas?

 

[Khalish]

If the polyps return to a skeletal ball like structure, I'm 99.99% sure it's a flower pot coral
Most people have bad luck with them although the it said that flowerpots from Australia are easiest to keep then from other countries

 

[organism]

It's an LPS Goniopora sp, careful those small polyp ones don't like too much light.

 

[Dosepher]

Gonipora?