1. (noun) vegetable caterpillar, Cordyceps robertsii - actually a type of fungus. When the caterpillar of some moths retreats underground to start to form into a pupa, preparing to develop into a moth, the fungus starts to grow using the caterpillar’s body for food. As the fungus grows, it forms a shell around the caterpillar’s body, and slowly the whole thing dries out. The caterpillar is slowly turned into a mummy and is dried and preserved in the fungal casing. The fungus feeds from the nutrients in the caterpillar’s body. It slowly grows a small stem through the head of the caterpillar, which is the part of the body closest to the forest floor. The stem grows slowly until it pushes through to the forest floor, eventually producing spores.