weird white armored thing?

[reefidiot??]

Hey, I was doing my weekly night hitchhiker check and I found this weird thing. I wish I could get a better photo but it's in the worst place to take a photo of. I just ran downstairs to check again and it disappeared which means it can move, or it got chomped on by my shrimp (Which I doubt) My best idea right now is a relative of an isopod. I also found a weird tiny shrimp thing which I panicked about because it had clubs just to realize it was just its extra legs. If you know what this thing is please let me know, I'm kind of stupid.

 

[EeyoreIsMySpiritAnimal]

Chiton. Good algae eater.

 

[reefidiot??]

Chiton. Good algae eater.

Cool

 

[ying yang]

Shrimp thing that has clubs ?
So like a smasher mantis shrimp ?
They come in on live rock occasionally I see a few others say and can start out small and in various colours

Ok just re- read your op and you say very small shrimp and just to realise it's extra legs so maybe just a simple ampripod which if is then just a pod so shouldn't be a problem