Even smaller ones are pretty aggressive. Have you ever seen a pod of them hatch? There are a kazillion and are born with territorial instincts. (They start trying to eat each other right away.) I hatched a couple of pods and had been told to scatter them in my garden, not put groups of them together because in each group only one would survive.

I have relatives in northern Oregon who have been posting photos of mantises (manti?) of this same size and they were laying egg pods. I wonder if this one was looking for a good location for that?