This evening when I went out to check my pepper plants, I noticed some black frass scattered over the light colored soil under one of my pepper plants. That's a tell-tale sign. It is best not to ignore it because large hornworms can demolish a plant in short order.
I looked at the plant to see if the culprit was on the pepper plant. Sure enough, I found some leaves that were half eaten.
It's amazing how something so big can be so camouflaged, but I finally found the critter that is pictured at the top of the post. I smashed it under a large rock. I will be sure to check carefully tomorrow morning to make sure there aren't other hornworms on my peppers or tomatoes.