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?

people to mistake mantis egg cases for other natural structures, such as wasp nests or fungal growths. Wasp nests are typically made of paper-like material and have a distinct honeycomb pattern, while fungi may have a softer, more irregular texture.
To differentiate a mantis egg case from these other structures, look for the characteristic foam-like texture and elongated shape of the ootheca. The egg case will also be firmly attached to a surface, often with a series of ridges or compartments visible on its exterior. Recognizing these features can help