What is this worm?!

[Chrille26]

Hi! I just fed my tank, 5 minutes later this worm shoots out of nowhere and attacks one of my clowns and my sand goby! Then it swims freely in the water like a eel.
I would never have caught it if it didnt get sucked stuck into a streamer for a second so I could scoop it out.
Any ID on it? I know for sure it attacked my fishes, it went straight for them. dang I hate all the crap housed in liverock sometimes. ;Dead

 

[lmm1967]

I put this up on youtube so more people can view it.

And I don't know exactly what that worm is - but I think you are very lucky to have been able to get it out as quickly and easily as you did.