Hermit crabs have shells that aren't part of their bodies. It can be shells or, heck, even garbage. Do them a good deed and don't pollute?

Did you know that New Zealand has 77 species of crabs? 78 if my friends and I migrate to those waters
en.m.wikipedia.org/wiki/List_of...

I think coconut crabs are really cool. But they scare me. I don't think I want to meet one.

Atlantic ghost crabs are my favorite