Please help identify...

[kyabk]

I found this guy growing on the glass of my reef tank. It is orange and has been getting bigger. At its ends it has white long tenticals. This is a picture of what is looks like. Its the best picture I could come up with for now. I know it wasn't there about 3 weeks ago because thats when I last cleaned the tank. Any ideas what it is? Should I let it keep growing? Think its harmful?

 

[Len]

Looks like a Foraminiferan to me. These guys are harmless protozoans that grow mostly in dark areas of the tank, capturing detritus and bacteria in their "tentacles."