Took some hunting on the internet to find what appeared on our front lawn after the rains - it's called a Basket Stinkhorn - said it had a rather bad odor but I didn't try sniffing it. Not bothering the fly!
Nice of it to show up in Halloween's traditional black and orange colors. Even Mother Nature gets into holiday decorating! lol about the fly not minding the scary aroma.
@falcon11 Yes, it is a type of fungus - definitely one of the strangest I've seen. The article said it smells like rotten meat on a summer day - glad I didn't get any closer.