caterpillar covered with white things
Hi- you are witnessing natural control of an insect pest (hornworm) by a tiny parasitic wasp. The white things are cocoons that the wasp larvae have spun after feeding inside the hornworm. A small adult wasp will cut a hole in the top and emerge. Always leave these parasitized hornworms alone so the wasp can continue its lifecycle. A large percentage of hornworms are controlled this way.