But some saw the image as a stark warning about marine litter and pollution.
One commenter said: "I saw this on twitter, the biologist who took the picture was making a point about marine litter."
Another person wrote: "This is actually pretty sad on top of creepy, since things like this is usually a result of a lack of available shells for the crabs, which they need. Don't collect shells with internal parts from beach areas. Crabs need them."