UFO triangular shape with purple lights fly over house from the lake North Saint Paul MN

School year of 2013. I was the only one who witnessed it for my family. About 7 o'clock at night it was starting to be winter. I was watching TV in my living room. I saw purple lights flash one time from Over the lake in the air. I ran outside to take a closer look my dog started barking. I went out to my driveway. My driveway is a shared driveway with my neighbor. He was gone. I looked up in the sky moved over to my neighbors side of the driveway. I sighted a giant triangular dark UFO figure bigger than 4 houses. UFO Flew low from the lake over a bunch of houses including mine. And I watched this UFO till I couldn't see it anymore. After I couldn't see it anymore the dog stop the barking. This UFO was pretty close to the rooftops of the houses close as within 200 feet from the rooftop of the houses. The UFO was long lengthy triangle having a narrow tip and a fat back. The UFO made no noise and it flash purple lights once. I tried to take a photo but my phone was dead. mufon cms# 82313