Help with critter id

Well I am back for questioning on the creature I found a month ago with my new coral addition. I am convinced it is some sort of cucumber, but it may be a slug. Haven't seen him in quite some time, but low and behold, he was crawling around some polyps this morning. Here are some pictures to help. I looked for hours, but can not figure out what it is.

 

There is a type of nudi that eats zoas....how are your zoas? Doing well? I can't tell from the pic exactly...

 

Ya. The zoas are doing well.

 

http://www.pelagiascuba.com/Images/gallery/sanjuans/sea_cucumber.jpg

Mine looks like that for the most part, but is solid brown.

 

It's a cucumber. Filter feeding type IIRC. Definitly not a nudi, no worrie

 

Thanks. I figured it was a cucumber. I just want to know what kind it is. It is driving me insane.

 

Is it black, or dark grey?

 

NONONO. It is like a dark tan.