Chiton?

[Reefer Dan]

I found this in my tank tonight and was not a fan of me shining light on it. It kind of looks like a chiton, but I’ve never seen a chiton that looks like this before.
Any ideas?

 

[Eric Cohen]

Is that a clam?

 

[fishguy242]

looks more like a type of isopod ,than a chiton.

 

[WheatToast]

Doesn't seem like a chiton; chitons only have a single row of shell "segments," and they do not have long filaments extending from their sides. It might actually be a scale worm, which can be predatory and do not seem to last long in aquaria according to this site:
http://reefkeeping.com/issues/2003-04/rs/index.php

Scale worm (bottom) and chiton (top):

More scale worms:

 

[EeyoreIsMySpiritAnimal]

I found this in my tank tonight and was not a fan of me shining light on it. It kind of looks like a chiton, but I’ve never seen a chiton that looks like this before.
Any ideas?

Looks like part of a bristleworm to me. Agree it's not a chiton.

 

[Reefer Dan]

Hmm possibly a scale worm. It doesn’t look like a bristle worm. It visually looked like a mix between and isopod and a chiton. Didn’t move super fast, but faster than a chiton (but the side legs were moving) . Thought this was kind of a weird thing and it’s hard to tell from the picture.
Thanks for all the ideas.