need to identify worm - anyone??

[Griffin]

Found a worm in my gf's tank and can't figure out what it is - anyone have any idea - when it comes out of the rock it seems to roll out from inside itself - then the mouth comes out then rolls back into itself once its done eating - thanks in advance
Rich

http://www.canreef.com/photopost/dat..._4088-med.JPG?

http://www.canreef.com/photopost/dat..._4089-med.JPG?

http://www.canreef.com/photopost/dat..._4086-med.JPG?