Skull Crab
Source: https://cdn.historydaily.org/
Definitely not something you expect to see, but this hermit crab walking around with a skull as its shell is as good as it gets. Hermit crabs need to search for their shells as they grow, changing homes as often as they see fit. In fact, some even fight another crab to take over the shell they want. Although we have a feeling that no one chose to challenge Skeletor over here.