Multiple witnesses observe small light near ground get large and fly off into the sky.My son, age 39 was in his back yard with friends and saw what looked like a firefly moving across the ground from distant trees to bushes in his yard just a few yards away. When the 'firefly' arrived at the bottom of the bushes it got a bit brighter. My son said 'walk with me' and nothing else to his 2 friends. When they came around the corner of the bushes, the 'firefly' suddenly turned bright blue and grew to the size of a baseball and shot at an angle over a parked school bus and disappeared into the sky. All 3 witnesses saw the bright blue baseball sized light and were startled considerably when it made the sudden physical change and took off. I was just at my sons place tonite for 4th of July celebration and both the other 2 witnesses were there, and made the same exclamation about how it startled them and how it zoomed into the sky from the base of the bushes. And they all said there was no sound from the object. It seemed to be a definite reaction to their presence.