Not a hitchhiker but still needing a ID

[tbcseod]

While hes (it) isn't a hitchhiker I'm hoping that this will be the best place to get a ID for this guy:
I got him a couple days ago from the LFS and he is really cool - stretched out to about 24 inches and thus far has cleaned all my frags without knocking a single one over (unlike my black sand-mopping cuke that has made a game out of it

)
The LFS called it a "Slinky worm" but I am guessing it is a species of Medusa cuke, now if I can only figure out what specific type of Medusa (I want to get another one for my other tank).
Any help would be appreciated,
~T

 

[mr_x]

medusa worm. i don't see any variations anywhere. it says they eat sponge poop...
"Although attractive to look at, you should resist any urge to purchase a species of Synaptula because most feed by mopping tiny particles of organic detritus and secretions from the surface of living sponges. Without the correct sponge species on which to live, they are doomed to a slow death by starvation in your aquarium."