All of the class were taken to see the stars around 10:40pm, but about half of the class left 10 minutes later. I stayed with the monitor and some friends, they were pointing and explaining constellations, I was really bored so I sat down on the grass and looked the opposite way. It was then when I noticed a boomerang-like object with a tiny dome and four flashing lights: yellow, blue, white and red. At first, I thought it was a plane, but I had seen planes flying a from a long distance and they did not fly that worryingly fast. I noticed that It suddenly stopped a couple times in the middle of the air for no apparent reason, then it continued it's path. It disappeared into the trees, but I didn't see signs of it descending. It came back another 4 times around our area, abruptly stopping and rerouting as if it was looking for something in particular. It also started to fly in circles at one point. I tried to tell my friends, and they saw it too but they did not seem to pay much attention.I have seen planes and jets flying at all sorts of distances and i repeat - this object was much faster than the usual. I tried to record and take pictures, but the sky was way too dark and the phone camera wouldn't catch what I saw. I know it sounds stupid and crazy without any evidence but It was not normal at all.