Favoritos de ttoshiro

I found this specimen while searching for Pacific sand crabs (Emerita analoga). I initially thought it was just a bitten portion of a dead crustacean. However, upon further inspection, it was living and moving, and when I put it back, it dug into the shore just as a sand crab would.

As you can see more clearly in the second picture, it had an antennule extending in front of it that was at least triple the length of its carapace, which is why I assumed part of it had been bitten. It couldn’t have burrowed any deeper than 20 cm.