Approximately 6" long, segmented shell, shades of brown, tan and white. I wasn't brave enough to touch it but my daughter did and said the shell was hard. The shell is edged by what appears to be a more flexible material.
Seen in the rocks. The tide had gone out and these creatures could be seen mostly in recessed areas of the rocks edging a cove. I saw only one that was not in one of the recessed areas but was on the rock in the open. They blend in with the rocks.
This was seen at Coco Cay, Bahamas.