Nobody seems to know what this is,anyone have suggestions?

[JenniferColor]

Hello fellow reefers,


We could use some of your wise suggestions on this creature we received from Florida on our live reef rock. Please note IT IS NOT THE BRAIN BLEACHED CORAL WE HAVE QUESTIONS ON. We unfortunately lost that coral during transport. We're having difficulty (and so is absolutely everyone else) identifying the big black creature right above it.

Some info on what we've seen.
It is 100% alive. It acts like a clam in the aspect that it is 100% attached to the corner of the rock.,and that it moves slowly like a clam..back and forth. Appears to wrinkle? When it moves and/or gets stressed. Outside is hard, almost shell like. It has these odd ridges that are stiff on the bottom. This little bugger has stumped everyone...We've ruled out sea cucumbers..we've ruled out sponges..and a variety of other very unlikely critters..we need our reef people to give it a swing.

 

[twentyleagues]

Hard to tell from the pics. It looks like a piece of rock. Can you get a video of it in action? Does it have an opening like a clam? Does anything come out of it like tenticals or mantle? If so in light or dark?

 

[JenniferColor]

Hard to tell from the pics. It looks like a piece of rock. Can you get a video of it in action? Does it have an opening like a clam? Does anything come out of it like tenticals or mantle? If so in light or dark?

Posted some new pictures, you had a good point..hard to give it a good guess when they're blurry. No tentacles from what we've seen. Hard to tell on the holes honestly, it's so wrinkled when it's angry and it's only been with us a couple days. It appears to be well established in that spot,whatever it is.

 

[Shon]

Looks like a pleated sea squirt

 

[IKD]

Is there a single ‘hole’ at the top? Could be a tunicate if some sort

 

[ISpeakForTheSeas]

The creature itself - as mentioned - is most likely a solitary tunicate of some kind, so it's almost certainly a harmless filter feeder. The ridges are interesting though: can you get some closer up pics of both an individual ridge and the whole line of ridges (preferably under whiter lighting)?

 

[Nicroper]

I would like to see a video of it in the water!

 

[kjkszpj9]

It looks like an underwater caterpillar to me lol.

 

[ISpeakForTheSeas]

The ridges are interesting though: can you get some closer up pics of both an individual ridge and the whole line of ridges (preferably under whiter lighting)?

Took me a while, but for anyone interested, I feel pretty confident the ridges are the eggs of a large snail. Unfortunately, I’m not sure what species, but there’s a good chance it’s a predatory one.