Help ID this worm

Hi folks,

Happy holidays to you all.

I need some help identifying this worm. I've done some searching but can't seem to find anything definitive. The worm is not unusual and I am certain it's quite common.

I'm just trying to determine it's name, what it eats, if it is reef tank safe, etc. Basically, should I keep him or not?

A photo is attached but here's a brief description. It's jelly-like and black. Segmented but depends on how much water it absorbs. When fully extended, about 12 inches in length and half-inch in diameter. It is covered with round "nodes" when fully inflated with water. The head looks somewhat like a feather star but the dark green "feathers" move individually like tenticles.

Thanks for your help.

 

Looks to be a medusa worm....why did you dig it out...?