A special kind of small sulfur-rich proteins, the metallothioneins, have an extraordinarily large capability for binding heavy metals. An international team of scientists has now discovered that the marine common periwinkle, which is widely considered a delicacy, contains the largest version of the protein found yet, with one additional cadmium-binding domain and a one-third higher detoxification capacity. This feature may help the snail survive in heavy-metal-polluted environments.