Snowflake shaped fan?

[SuncrestReef]

I have several feather duster worms in my tank, but recently I've started to notice something else that sort of looks like a fat feather duster, or a snowflake. Any idea what these are?

 

[MTBake]

Clove polyps?

Edit:

Pretty sure that is a clove coral.

 

[AbnormalReefer]

Some type of soft coral polyp in the Xeniidae family for sure. Kind of looks like blue sympodium but, well.... not blue. If this is the case, get it out ASAP! These polyps spread rapidly and, worse, unlike things like aiptasia, nothing known to our tanks eats them!

 

[samnaz]

I agree it looks like sympodium.