What are these, what can I do?
I have had these worms? Caterpillars? appearing in bathoom for about a month. Now I have a seemingly dead tree and bush and the ground is littered with these cocoons hatching caterpillars (?) I applied powdered Sevin just now. Any idea what they are? How to prevent? Do they eat fiber (i.e., clothes!) I will try to get pic of full creature. Thank you!
These are bagworms. They have killed your arborvitae, but you could have picked them off or sprayed earlier and saved the tree. Here is how to manage them: https://extension.umd.edu/hgic/topics/bagworms-trees-and-shrubs
They are plant eaters, so they would not eat clothes. They are not indoor house pests, but there were so many they just wandered in.
Sevin is a highly toxic pesticide that we don't recommend using because of it killing beneficial insects such as pollinators. You also don't want to track that into your house.
Keep an eye on your other evergreen that we see in the background of the second photo. Read the webpage above carefully, so that you know what bagworms look like at different life stages. They are simple to pick off and drop in a bucket of soapy water before they destroy your landscape.