green slimy/ blobby thing

[melissfish]

can anyone identify this. It has been in my tank ages but i only ever seen a green flat forked tongue looking worm, and his middle stretching around thru the rocks sometimes up to a metre long. Today i saw the other end, it was a blobby looking green ball that bounced around and contracted to change shapes constantly, i could also see some kind of stomach function inside it and a small opening, maybe a mouth. Here are some pics sorry about the quality.

http://www.flickr.com/photos/melissamurray/23437207/

please look at the first six pics to see different pics of him

 

[Fluff]

Hard to tell but I think what you have is a peanut worm. They are harmless scavangers.