At first, I thought this was a small twig that had somehow gotten stuck on the newspaper attachment to the mailbox. It's not an uncommon occurrence, but there was something un-twiggy about the object, so, instead of just trying to sweep it off with my hand, I gave it a closer look and, of course, it turned out to be a remarkably deceptive "inch worm" caterpillar doing a fine job of mimicking the tiniest of tree branches. I can't be entirely certain of its identity, but the overall grayness and nondescript markings suggest that it might be a One-spotted Variant. According to caterpillar-master Dave Wagner, this species is "among our most ubiquitous and numerically constant caterpillars on trees and shrubs.... If you plan on doing much caterpillar sampling, you must learn this inchworm." I'll put it on my schedule, along with a prayer that I see it again and get a better set of ID images.