Outside Wellton, AZ,summer of 1975, my brother and I were outside smashing aluminum cans. We both were suddenly aware of a hockey puck sized UFO hovering very close by as if watching what we were doing! We kept looking at it, trying to figure out if it was some sort of weird bird or huge insect as it hummed, almost like the noise that a hummingbird makes. It was NO hummingbird. It was shaped like a hockey puck (round), a black/dark grey dull surface, that was not smooth looking. It looked like the color of a gun barrel but not as smooth. The object hovered, moving smoothing toward us, then backward, it moved quickly back and forth, left and right. I was slightly fearful, unsure of what it was and afraid it might hurt us. My brother started throwing rocks at it, trying to knock it out of the air. It never landed the entire time we observed it. The object easily avoided being hit, zipping away, then back again almost as if playing with us! It never emitted any lights of any kind, it simply hovered, slightly humming/buzzing as it did. This went on for over 15 minutes, literally, as we tried to knock it out of the air! As we started moving closer each time, running at the object and throwing rocks, it took off quickly, flying low through the desert floor, easily avoiding the native brush and bush as it flew. It came back three times. Each time, moving so fast, it was very difficult to keep track of all at once. The last time it flew off, it flew low, and then upward, quickly disappearing into the sky.
A few months later, I can't remember the exact date, I was alone, biking home from a friends house, about half a mile from home and the object, exactly the same as before, flew up beside me as I rode my bike, moving easily with me along the road. It hovered around a foot from my face. I was terrified! I tried to go faster but it (of course) easily stayed with me. It did not do anything but simply hover/fly along with me as I biked home. Again, it was like it was observing ME! I will admit that this encounter freaked me out considerably as I was alone, still a substantial way off from my home. I did not feel safe at all. I put my head down and rode that bike as fast as it would go, refusing to look at the object any longer. I don't know exactly when it took off, but when I got to the driveway and looked up, it was gone.