This is an interesting comment : "This is stupid. 1. Consult with a marine biologist to find out if there is a real shortage of shells for hermit crabs to use

This is an interesting comment : "This is stupid. 1. Consult with a marine biologist to find out if there is a real shortage of shells for hermit crabs to use. Tip: There isn't. Source: I'm a marine biologist." EDIT : I removed the last half of the comment because it addressed the issue of dumping plastic into the oceans, which has been addressed by someone else here (they often use bioplastics for 3D printing).