Can someone ID this for me

[l8agin]

Just moved rock and this is on the backside can someone tell me what it is?
It is the yellow and red on bottom of rock.

 

[9supratt4]

Looks like an arrow crab.

 

[rebelprettyboy]

also looks like an arrow crab to me?
How could u not notice it was there? Did u not buy it? Did it come as a hitchihiker?

 

[coraljunky]

Likely a type of sponge. From this pick it kinda resembles a gorgonian.

 

[cranberry]

*gets out reading glasses*
*whips out magnifying glass*
I have no idea. If it was behind the rock out of the light for any amount of time I would guess it's something nonphotosynthetic or something very hardy.
Ya, not that helpful I know.....

 

[9supratt4]

What are we talking about?? The crab or something else in the picture that I don't see....lol

 

[aquaguy24]

all i see is an arrow crab,lr and ls...

 

[l8agin]

It is to the right of the crab almost at the bottom of the rock its a little yellow spot andhas red spots on it.