This big amazing creature landed on the window screen outside my front door and remained there for at least 10 hours. I learned that it's a black witch moth and that if you believe in superstition, it's not necessarily a good sign to have one on your window.
On the other hand ... at least according to Wikipedia: "In South Texas, if a black witch lands above your door and stays there for a while you will supposedly win the lottery" and "In the Bahamas, where they are locally known as Money Moths or Moneybats, the legend is that if they land on you, you will come into money."
Fortunately, I'm not all that superstitious. But they do look big enough to be carrying some cash ... maybe even their own wallet.