Found this hard, foam-like brown structure attached to a fence post in the backyard. I was about to scrape it off but hesitated. What is it?

 Strange Foam-Like Structure on Backyard Fence? Here’s What It Likely Is

If you’ve spotted a hard, brown, foam-like mass attached to a fence post in your backyard, your hesitation to scrape it off may have been a good instinct. What you’re likely looking at is an egg case, known as an ootheca, produced by a species of