weird black thing I saw

This is weird, I heard a military helicopter, so I looked outside my window and instead of seeing the copter I saw this black thing hovering in broad day light, I couldn't even get the exact shape, but it looked somewhat circular base. It hovered in mid air for like 10 seconds and then just sped away, like super fast over this hill. And then I saw the chinook looking helicopter slowly making it's way over the same hill

I believe you!
Please tell me more about your fascinating encounter!