I came across this on my tomato plant last night. My first reaction was "Wow, that is a REALLY weird looking caterpillar." I spent a few minutes searching for information on it and learned that it wasn't just a caterpillar, it was a Tomato Hornworm covered in Braconid Wasp eggs. Turns out that the little wasps inside the eggs feed off of the caterpillar that is feeding off of my tomato plant. Eventually the caterpillar will die, the wasps will hatch and the cycle begins again. A bummer for the caterpillar, but a welcome event in our garden.