crab ID please.

[dougie]

got this crab as a hitcher on my rock, Good or bad?

And does anybody know what this weird coral thing is? been growing for about 3 weeks.

Thanks for the help.

 

[LeslieH]

From the side view the crab looks like a xanthid which means like most crabs it's an opportunistic feeder. In the photos it seems to either be grazing on the rock or waiting for something tasty to walk by. If you don't want it why not take it back to your LFS or pass it on to someone who does.

The red appears to a type of bubble algae. Try posting in the algae forum for better information.