Needing a couple hitchhiker IDs on elephant ear mushroom rock

[bdieleman64]

I got this elephant ear mushroom a couple months ago. It's usually hand size but today it's been shriveled up and I noticed these on the rock that has been hiding under the coral. Seeing if I could get an ID on them. Good or bad?

 

[threebuoys]

Maybe feather dusters?

 

[ISpeakForTheSeas]

Welcome to Reef2Reef!

Is the one on the left solid or squishy? If solid, it may be a bivalve; if squishy, probably an anemone. A closer up pic would also help here, though, as it seems to have tentacles/tentacle-looking things around the edges.

The one on the right is definitely a feather duster worm - a harmless filter feeder.