Weird snail clam hybrid looking creature

[seth16]

I've just noticed this strange baby oyster looking shell attached to a rock with a small colony of ricordeas, as far as I know it's never been there. It also seems to be alive because it goes in and out of its shell if disturbed, it sorta looks like the body of a snail, any ideas?

 

[seth16]

Here's a clearer picture

 

[Zack K]

@lionfishliar

 

[Tahoe61]

Are you sure it's not a Vermetid Snail?

 

[reef lover]

Looks like one....

 

[Lionfish Lair]

@lionfishliar

I swear I've never lied about lionfish!!

I actually think I'll guess barnacle. I know you're thinking

but hear me out. Can you see the resemblances?

 

[Tahoe61]

I can see it Renee.

 

[Elegance Coral]

chaetopterid worm
parchment worm

 

[seth16]

Came to the conclusion that it's a vermetid snail after I watching it eat some algae.

 

[Lionfish Lair]

Is he in a clam shell?

 

[Lionfish Lair]

Wait now... you saw it eating algae? That's not how they eat. They cast webs to drag stuff back and catch particulates and what not. They wouldn't be picking around eating algae. What did you see it doing exactly?

Could you catch it on video? Maybe a few more picture?

It also reminds me of the siphons of a clam. Not the long thing to the left, but the two lower bumps to the right. reminds me of a Piddock clam.

 

[Lionfish Lair]

Here are the two things I think look like siphons.