Spotting

Sorry about that. I found it in "other" along with several other arthropods and I made the change as a part of this maintenance and I should have read it in detail.

I am far from the right person to help with this stuff haha. But that's what is so great about this site, lots of people with different areas of expertise! Hope you get it figured out

Hm it could be an algae, it's a weird color for it though. And yeah, I found it just washed up on the beach, the crab was dead and I'm wondering if this might have killed it :(

Just move it back to the fungus category lol :) Is it not a type of algae? Looks kind of wet?

This spotting wasn't for the crab, it was for the fungus stuff growing on it's claws though!

Moved your crab to the category Arthropods. :-)