Huge blasts of spinning lights(3) scanned at least an acre of land until they zeroed in on us and chased us under a tree where we hid.

Me and a freind were out at Lake Travis having a chat about sience fiction stories when I noticed a slow moving light out of the corner of my right eye. It went silentley through the trees then dissapeared. 
I thought it was a car so I ignored it. Suddenly 3 gigantic spotlight beams blasted from the treetops and began scanning the ground, they were spinning in huge sweeping search patterns. We were awestruck and wide-jawed and then one of the 10 foot wide beams scanned us passed us and immedeatley swept back on our bodies. Both other search beams then shot on our bodies, we were completley exposed and frightened. 
We ran, hearts pounding and completley freaking out under a tree, where the lights followed and shone through the folliage for a horrifing breif period of time. I think I was praying by then. The lights shut off with a klunking sound and we each fealt safe that we were not going to be harmed. 
We walked out from under the tree and saw a large triangular shaped object floating over our heads. We watched it drift off over the glistening water as it made a very low frequency humming sound. There were 5 lights on the back of the ship that blinked in sequence from right to left one at a time, very slowly and methodiclally, amber in color. 
It drifted ever so slowly over the silent surface of the water for several min. untill it faded into the horizion. 
We both went back to our park bench, sat down began talking about what we had been talking about before like it had'nt happened. 20 min. later I remembered what had happened and asked my freind, "what was that?" and the said "oh, you mean that ship?" I said "yes" then he said "I don't know". How did we forget what had happened? How did we remember? I was always affraid to let this information out to the public but now I know that my story is a dime a dozen.
Witness, who elects to remain totally anonymous, indicates that date is approximate.  PD