Wife was cleaning up supper dishes and she frantically called me to the kitchen to look out the window - over the lake (our kitchen - bay window is only 30' from the lake). We observed a small (?) greenish 'light' hovering directly to the east - at an unknown distance but at maybe @ 22 degees - over eastern Hazelton or western Wealthwood township - nominally 2 - 6 miles. It made some movements and after a minute or two traveled at a speed greater than any aircraft we know to the north. We then both ran outside and onto our dock. Still visible (at about the same unknown distance)it traveled to a northerly point and stopped, hovered a minute and then zipped back near it's original position. At which point it went straight up ... about an additional 10 - 20 degrees. It then descended back down, moved towards the south - then east until out of sight. No sound. Very unusual. The speed, and ability to make quick, 90 degree turns - we have never seen anything close to these. Total time witnessed was about 5 - 8 minutes.