What is this thing attached to my sun Polyp???

[fishygayle]

This thing came attached to my sun polyps rock. It pulses in and out. It kind of has a mouth at the top. It opens...haven't seen it catch anything. You can see the mouth-like part in the first picture.

There is also a mysterious orange circular thing at the bottom. Does anyone know what these are?

 

[dragonladylea]

IMO I would have to say a spiny oyster and a red sponge both are nice to have as hitchhikers.

 

[Anonymous]

I would say the same....spiny oyster.