Mexican jumping bean
Mexican jumping beans, native to Mexico, are seed pods that have been inhabited by the larva of a small moth. The "bean", usually tan to brown in color, "jumps" when heated, because the larva spasms in an attempt to roll the seed to a cooler environment to avoid dehydration and consequent death. They are from the shrub
Sebastiania pavoniana, often also referred to as "jumping bean". However, they are not related to actual beans, but rather to spurges. The beans are considered non-toxic, but are not intended to be eaten. After the moth egg laid on the plant hatches, the larva eats away the inside of the bean and attaches itself to the inside of the bean with silk-like thread. The larva may live for months inside the bean with varying periods of dormancy. If the larva has adequate conditions of moisture and temperature, it will live long enough to go into a pupal stage. In the spring, the moth forces itself out of the bean through a round "trap door", leaving behind the pupal casing. After its metamorphosis, the small, silver and gray-colored moth lives for no more than a few days.