Slug thing with cuttlefish looking head ID please. Very strange indeed

[distractor]

Hi there,
My tank has been setup for a few months now but I have been trying to work out what has been churning over my sand since I have no Hermits or Cerith snails. I was looking at the tank tonight with the torch and saw this ugly fella.
His rear end looks like a spider sac :eek1: and its "head" sort of looks like a cuttlefish? What the hell is it and is it harmful? I'm guessing not though since it's just sifting sand. Soon after getting these pics, he retreated into the sand again.

http://i33.photobucket.com/albums/d89/pelvis_3/Various/IMG_5996.jpg

http://i33.photobucket.com/albums/d89/pelvis_3/Various/IMG_5986.jpg

http://i33.photobucket.com/albums/d89/pelvis_3/Various/IMG_5989.jpg

[greech]

Would have to say cucumber but what species, I don't know. I wouldn't classify it as harmful and as long as you can keep it alive, it will likely a beneficial member of your cleanup crew. It looks like a sand sifting cuc and not a filter feeder so it should be a bit easier to keep.

[Sugar Magnolia]

I agree with Graham. It's definitely some type of cucumber. Cool hitch hiker!

[Sk8r]

I'm thinking that COULD be a cowrie, a variety of snail-type creature. Google it. They extend a cover over their shells, which is why their shells always look so bright and fresh. They're good (expensive) algae eaters, and usually stay to dark places.

[distractor]

Thanks for the replies folks. Hey Sk8r, I don't think it's a Cowrie. It's head is completely different and does not have tentacles either. I just realized that it's head looks much like one of those creatures from 'Tremors' haha
I will watch the critter closely to make sure he wont do any damage.

[Sk8r]

Tiger cowrie with mantle. This that you have would not be a tiger, but I'm not convinced it's not a cowrie. :lol:
http://shells.tricity.wsu.edu/ArcherdShellCollection/Gastropoda/Cypraeidae.html

[Sapooloo]

baby graboid:P

[distractor]

Do you think I should touch it and see if it retracts it's mantle?
That is, if it's a cowrie.

[Jlobo]

I just looked up tons of images of cowries and what you have looks nothing like them. Weird!

[greech]

Cucs and their mouths come in so many shapes. Some are just complete scavengers and some are specialized eaters. I really think that is a cuc. How is it behaving? Is it trying to bury itself at all? Has its mouth opened at all?

Definitely looks like the sand creatures from 'Tremors' :)!

[distractor]

The other night when I was inspecting the tank, I noticed something crawling under the sand at the front of the tank but just thought it was a Stomatella but then when I saw it last night out of the sand, it freaked me out. It was slowly crawling along just like a land based slug would and sort of looked around a bit and then slowly descended under the sand again when I kept the light on it for too long.
Thats the only info I have on it until I see it again.

[distractor]

Ok. So it was out again just a minute ago so I reached in and gently touched it.
It did not retract it's 'Mantle' and it was very soft indeed. As it crawls along, it leaves behind a type of mucus layer that keeps it's skin shiny clean. I got a crappy vid of it retreating into the sand.

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[Sk8r]

In-trust-in!

I'd suggest asking Leslie H over in Other Inverts. I think you've got an odd one!