Thanks bangguy,
I am hoping to ID it positively.
It lives in a slime tube, kinda looks like spider web. It is fairly long, maybe 12-18" and is opal colored. It has a spikey head, but it can retract its barbles and can pick things up with them.
I once fed it a shrimp pellet which it snatched up and retreated to its cave.
it appears to have a row of legs on opposite sides of its body.
I have noticed no damage to my fish or inverts that might be attributed to a predator, but I would like to ID this thing for curiositys sake, if nothing else.