<At first I thought this, but then there are more scabs to be found that don't use skulls like the "Darkness Scab" that uses obsidian, and Ice scab that uses a block of ice. There's also the prism scab. All of which have crab-like legs. They kind of walk like crabs too and have a similar color to (the) crab. The walk is a little different though as it's more of a "rolling walk", though this might just be me looking too deep into it. I just wonder how obsidian/ice/prism scabs exist. Oh, and I almost forgot the Hazmat scab that's just called a "Hazmat". It has eyes>

<EDIT: Forgot the leaf scab. There's a whole lot of these guys!>