Just tell them that they shed their shells like crabs.

( Dr. Shambolic je suis charlie, Wed 24 Jun 2009, 22:56, archived)

for some reason i am now imagining them to be like giant beetles
having wings under their great backs. if i wasn't going to bed, i'd photoshop it
( spacefish bong!, Wed 24 Jun 2009, 23:02, archived)