Bright green light zigzags over the Gulf of Mexico.While taking out the trash to the side of the house in which I live in Naples Park, Florida, I observed a bright, steady green light traveling rapidly due south to my west. I at first thought it was a helicopter flying low over the area of Vanderbilt Beach on the Gulf of Mexico, but realized that the light was not "strobing" as any F.A.A. certified aircraft would. Venus was very bright at about 20º from my southwest horizon, and the light was heading in that direction until it stopped, remained stationary for a few seconds, then began reversing its course to the north. As it did so, the light began strobing brightly, but no other lights were noticeable. As the light passed behind a tall neighborhood tree which blocked my view, it apparently again stopped, for it never emerged from behind that tree. I walked down the street to change my perspective, but could see no trace of the light thereafter.