Sea cucumbers are exploited by humans, mainly as food. Despite their name, they are not eaten whole like a cucumber because their bodies contain toxic chemicals. Instead, they are boiled to separate the external body wall from the organs. The body wall is served as a delicacy in Asian cuisine (trepang) or dried for use as flavoring. It turns out that the toxins make sea cucumbers valuable for other uses. Fisherman put ground sea cucumbers into the water to cause respiratory problems in fishes, making them semi-conscious and easier to catch. Sea cucumber toxins have medicinal potential for humans. Pharmaceutical companies are studying their properties as antibiotics, anti-inflammatories, and/or anticoagulants. Their usefulness has put sea cucumber populations at risk, for example off Ecuador's coast where they are heavily fished for export to Asian markets. Concern about overharvest has led Ecuador and other nations to include sea cucumbers in marine management plans.

Echinoderms move using rows of small tube feet powered by a fluid-filled (water vascular) system. The fluid travels from central, circular canals out through radial canals like the spokes of a wheel. Along the spokes are the tube feet, which typically end in adhesive pads. Each tube foot is kept firm by internal fluid pressure. By sticking down and unsticking in coordinated waves, the tube feet inch the animal along a surface. The water vascular system used for locomotion can also function for feeding. Some echinoderms pass small pieces of food along from foot to foot until it reaches their mouths. The otherwise soft echinoderm body gets the support it needs from a skeleton made of calcified pieces (ossicles). Ossicles often have spiny projections that give the overlying skin a prickly appearance (echino = spiny; dermis skin).