I saw it lurch by the window, and ran out with my camera. It’s not the most graceful of insects, and indeed its wings are a vivid blue/green. Loud too. It headed for a tomato bed. I got one shot off, but missed it. It looks like a shield bug, but unlike ones I can find online. After sloppily landing in a few other places near the ground, it disappeared once again.
It appears to be over an inch long, possibly an inch and a half.