You lucky duck! I haven’t found a single one yet at my house!
As others have said, this is the egg mass, or “ootheca,” of a praying mantis.
This one is native to the US! The Chinese mantids make oothecas that are more sphere-shaped.
Enjoy watching the babies hatch if you can, it is quite the sight! Great garden buddies to have.
I think this is a European mantis ootheca. Also invasive.
Damn what are the characteristics so I don’t misidentify in the future?
Have a look at this link. It has a photo comparison of various mantid oothecae. It looks like the native Carolina oothecae have a brown and white pattern, whereas the European ones look kind of like a loaf of sourdough, as someone else mentioned here. :)
Wow thank you so much for this knowledge! I will be sure to share with my parents who are also mantis fans.