They like to crawl up the large pine tree outside the door. The pine needles are their source of food. Every once in awhile one loses its footing and falls down with a thud. I have yet been hit by one but have had a couple of near misses. Beans ignores them thankfully. I just have to be careful not to step on one for that would leave a very gooey mess on my shoe. Evidentially they do mass migrations across Highway 97 south of Bend, OR. The road will become so slick that the highway department has to lay sand on the roadway. They are about the size of your pinkie finger.
One day a wasp trying to carry a caterpillar walked by and rolled down into the fire pit (no fire). Try as she might she couldn't maneuver the paralyzed pillar back to her burrow to lay eggs on it.
She eventually gave up and went on to search for a smaller snack for her upcoming brood.
When they are ready for the next cycle of their lives the caterpillars burrow themselves underground. I haven’t seen any in the last couple of weeks so this must be where they are now. In their burrow they weave a silk cocoon and will morph into a moth. The fascinating part is that the moth will not emerge until next summer or the one after depending on weather.