Blue outlined jellyfish-like craft, transparent center at first, then pulsing yellow, then pulsing purple

The night before my 12th birthday in April 2007, I was having trouble sleeping.  I was young, excited about the following day's events.  
Around 11 I finally drifted asleep, only to be woken up a few hours later by a bright, pale-blue glow coming through the blinds of the window beside my bed.  Being a child, I figured it was the blue sky of morning.  
I stood and pulled my blinds up as I did every morning.  When I did I was greeted not by the sky I'd been expecting, but by the dark night sky.  I looked around for the source of the light, and not finding it, I went to get a glass of water.  I figured I'd imagined it. 
When I came back to bed the light was back, and this time I could see the source.  There was a large, saucer-shaped craft in the sky above the forest behind my house.  It looked almost transparent in the center, and glowed blue around the edges, looking almost jellyfish-like. 
I stared for a few minutes, stupefied.  As I watched, the center pulsed yellow and! came closer to my window.  I tapped the glass, I don't recall why, but when I did it pulsed purple very quickly five times and took off. 
I dove into my bed and tightened the covers around me, something about the craft filled my chest with cold fear
Witness indicates that the date of the event is approximate.  PD