All crustaceans with an outer shell do it. It was funny the first time my cleaner shrimp shed her shell (yes she had eggs once), I literally thought she had died and the other critters had eaten everything but her shell. She came out of hiding a day later, and a tiny bit bigger.

I abhor spiders and arachnids, to the point of having nightmares! My boys thought it was funny to toss an old spider skin at me.