Hitchhiker ID help - is this a peanut worm?

[SFREEF3R]

I found this worm-like hitchhiker in my sump. It has been extending and contracting as in the images below. When extended it reveals some sort of appendages -they are hard to make out though as they are quite small. Fully extended it's maybe 1/2" long.

My best guess is peanut worm from images I've found on line. Anyone else have thoughts?

 

[KrisReef]

I agree with your identification of this peanut worm. I have found them once or twice in my tanks in the past and they did look like yours does. I Googled to find out about the tentacle surrounding the mouth. Your photo shows that very well, and I had not noticed those in my past peanut worm encounters. I've always heard they were ok filter feeders for reef/fish tanks so I'd keep it if I found it.