The sighting happened while fishing on lake Tawakoni approx 50 miles north east of Dallas Tx. I fist noticed the craft about 500 yards away looking for seagulls gathering over the lake which is a fishing techniques used to locate schools of stripers feeding of shad... while looking at the BIRDS through binoculars I spotted something odd looking that was shiny. I thought it was a balloon at first.... as it got closer we realized it was moving to fast and changing directions and height. My fishing partner and I watched it for the next 5 minutes or so ascended rapidly and changed directions several times. At one point IT WAS SO CLOSE approximately 50 ft...hovering then descending toward my boat, we thought it was going to land in the boat. I quickly got the boat started and gunned it and drove about 1500 yards the craft followed the boat. I changed directions and headed due north and drove about another 250 yards... the craft followed us again.... then stopped approximately 30 to 50 feet directly behind the boat, it hovered there for a minute or so silently... Several times I wanted to take a picture but something inside my head said don't take you eyes off it ..... my fishing partner was scared and yelled to me lets get out of here. IT WAS SO CLOSE... 30 FEET OR LESS we thought it was going to land in the boat again.... it was strangely scary..... BOTH OF US HAVE never seen or experienced anything like this before. Then, in a blink of an eye it accelerated and instantly disappeared into the distance in a fraction of a second. IT DISAPPEARED SO FAST WE JUST STOOD THERE STUNNED LOOKING AT EACH OTHER.....At several points we saw something like a white light or beam or what looked like a probe come out of the craft. LIKE A TENTACLE OF SOME SORT.My fishing partner is a scientist and electrical engineer and I my self am a successful Energy business owner. We were both stunned and bewildered AND SCARED AT THE SAME TIME. The craft was not that big in fact it was small approx 4 or 5 feet in diameter and may be 2 feet in height. Super shiny, metallic in color... like chrome with a slight blue tint. It was shaped like a hat.