ID: sea cucumber/apple?

[JakStat]

i got this hitch-hiker on some live rock. it only "opens" at night.

here's a shot of it closed:

here's a shot of it open:

these are the best views i have of it, a couple seconds after i turn on the lights to get a pic, it snaps shut, so this is the best i can do.

thanks!

 

[JakStat]

cerianthid.

yeesh.

 

[graveyardworm]

Cerianthid is a tube anemone. The pic you posted really doesnt resemlbe a tube anemone. Appears to be moreof a filter type of critter. Perhaps like you posted originally a cuke. If the cuke is happy it may stay put for awhile.

 

[ginger7286]

Looks like a cuke. All of mine have the same mouth appendage which they readily open anytime day or night (usually night) to filter feed. When not lying immobile they move about the sand bed eating the detritus.

 

[coralnut99]

Cukes tend to be pretty mobile. Has this moved at all? Pretty cool lookin'!