Craft sighted that looked like airplane, then emitted big blue ball of light and vanished.I was sitting in the attic of my garage playing a keyboard that sits in front of a large window. I stopped playing to look at the sky when I noticed I could see the moon in the daylight, and it looked quite beautiful.As I'm looking at the sky, I get the bright idea (influenced by an internet forum) to pulse a laser into the sky as it is rumored to attract strange craft. Not believing this in the slightest, I pulsed the light about 10 times in a few seconds. I then noticed a craft slowly flying across the sky to the lower right of where I had shined the laser (at least a couple of miles in the air).When I saw the craft I immediately ceased to use the laser, as I was unsure as to if it was a plane, and the last thing I need is to cause a pilot some distraction. I continued to watch it fly across the sky from west to east at speeds a typical airliner would be flying. The intriguing part was that I could see no wings, no tail fin, and no discernible markings that you can usually see on airliners as they fly in the area.As the craft moved further east, my opinion that it was an airliner went out the window as a large electric-blue ball of light quickly appeared behind the craft, and then in disappeared entirely. The sky was crystal clear in all directions, and at the speed and direction it was flying, it should have continued to be visible for at least another ~3 minutes. It simply vanished.