UPDATE: Last year I posted a picture of a bug I spotted while walking at Salem Lake. I'd never seen one like it before, and thought it looked like a bug in a bubble.
While looking up another critter from the insect world, I recognized this as my bubble bug.
Mystery solved. It seems the little guy is called a Tortoise Beetle. While the markings on my beetle aren't identical to the one I found online, tortoise beetles come in many other colors and patterns.
Varieties of the tortoise beetle are found throughout the world. They are common, and apparently harmless to people. Agriculturally considered a minor pest, they can attack foliage but rarely cause significant crop damage.