Decorator crabs live off the California coast, among other places. They create their own camouflage by grabbing little bits of seaweed and shells, then hooking that stuff to their shell using Velcro-like hooks called setae. On occasion, these crabs even hook living anemones onto their shells, creating a tiny moving habitat.

In this video from Deep Look, we get to see decorator crabs up close (indeed, in 4K resolution). The best part is the "moss crab," which is delightfully hairy. Have a look:

If video isn't your thing, read this writeup from KQED Science.