I thought that this might be some kind of bagworm, but I couldn't find anything like it - though I swear I've seen it before.

Coincidentally, I was looking for just something like this for a diagnosis that I was trying to make at work. The description was a "cone-shaped" critter feeding on raspberry. After some research though, I decided the sample inquiry may most likely be one of those caterpillar dropping mimicking leaf beetles, but weirdly this guy (my original guess) was on the cloth seat of our truck when I was riding home.

Unfortunately due to where I found it, there is no host information. It may have crawled there after hitch-hiking on hubby's hunting clothes (Turkey season). I put it in a petri dish where I hope that it will pupate. Hopefully it was wandering and had finished feeding as I have no idea what it might eat.

The measurement is of the "cone" which to me looks to be made of very precisely placed droppings on the main body and a little more loosely placed on the "hood" which seemed to be more flexible and able to allow the caterpillar to maneuver. Weirdly, the caterpillar itself looks somewhat similar to a casemaking clothes moth, but my perusal of the Tineidae didn't find any that looked anything like it either.