My family was on our way home from a cookout at my grandparents' house when I, from the backseat of our minivan, saw a 50-60ft-wide black triangle, hovering just above the treeline. It was late fall, and with most of the leaves already fallen, I was afforded a clear look at the object. It was definitely a solid craft, with a white light on each vertex. It was otherwise devoid of any distinguishing features. I pointed it out to my parents. My mom leaned against her window to see it and gasped, prompting Dad to crane his neck forward so he could see out the windshield. He expressed confusion over what the craft was, and began to drive faster. Around this time, both of my sisters woke up from their naps. One of them saw the craft, but the other refused to look. She just became frightened and began to cry. The object began to follow us, and Mom rolled down the window to see if we could hear any engine noise. We couldn't. Somehow, we lost the thing and made it back to the highway. I always assumed it was just a secret military craft, out on a test flight in a pretty sparsely-populated area. Soon after the event, however, my father and two sisters lost their memory of it. To this day, only my mother and I remember it happening, and our memory of what happened after we actually saw it is fuzzy. I am not aware of experiencing any missing time on that night or any other, but I can't help but wonder if the object came from...somewhere else.