Sand Star missing digits

[Aquaholic]

I just noticed my sand sifting star is missing 2 full digit and the other is half off, why? My other star is fine (blue lactina)

Could I have pinched them? (was moving rock around recently)
I also have hermit crabs, about 10 or so, could they be the culprate?
I have an emerald crab did he do it?
or is there some unforseen force acting upon the little guy?

I don't think it was any fish (3 damsels, a goby)

Thank you,