Interesting Ball critter

[gbroadbridge]

Hi Folks,

Six month old nano tank, and all of a sudden this critter shows up wandering up and down the glass.
Never spotted it before.

Anyone know what it is?

 

[Cell]

Tuxedo urchin. Nice hitchhiker!

 

[gbroadbridge]

Tuxedo urchin. Nice hitchhiker!

Thanks for the ID. Never seen one before.

Guess I'll move it from the 12g nano to the 75g.

 

[Cell]

Did you add live rock? That's a pretty good sized hitchhiker to not notice.