Taking that beautiful snail shell could increase the cost of housing for a hermit crab or the small shrimp that needs it next. The beautiful conch shell that calls to you is actually an octopus ...

you notice a conch shell. Stoutly made, it has six heavy spikes coming off it. Perhaps the maker is within. Or perhaps the maker is long dead, and the shell now belongs to a hermit crab.

Instead, hermit crabs have a hard exoskeleton on the front part of their bodies but a soft tail on the other half, which they protect using the discarded shells of other animals, like whelks.