If you grow tomatoes in your yard, you have probably seen HUGE, green caterpillars on the plants. This is the tomato hornworm, and it can munch a tomato vine right down to the skeleton. However, the little Cotesia wasp just loves the T.H. Why? The wasp lays its eggs inside the hornworm. As the eggs hatch, the larvae eat the caterpillar from the inside out — while the hornworm is still alive! Eventually the little wasps chew through the hornworm's skin and spin tiny cocoons all down its back.