giant black hornet

Hello, this is my first post. I've had this giant creature in my back yard for a few weeks, but tonight it got way too aggressive for comfort. I live in Vermont, and this is not the first time I've seen one of these. The ones that I saw at my old house (northeast part of the state, very cold climate) had white accents, but I couldn't see this one well enough to determine if it had them as well. This is a huge black hornet looking insect. It looks like a cicada killer crossed with a bald faced hornet, but it retains the size and weight of a cicada killer. Very large insect. I have been searching for two hours, and I've tried searching in the past out of interest and curiosity, but it doesn't seem to exist on the internet. I've seen others describe it, but not get the correct identification. I can say that it is not a great black wasp or tarantula hawk, and if it is a bald face hornet it is waaaay bigger than most specimens. Every one I have seen has been the same size.

I was sitting in the yard this evening, and I had to flee the area because this creature would not stop buzzing me. As I was briskly walking away, it followed and landed on my back. I hate the idea of killing something that I would normally enjoy and respect, but I have a two year old and I don't want it doing the same to him or worse. I recognize that it could have been defending its nest, but I tried different parts of the yard and it would not leave me alone. I'm afraid I might have to hunt it down.