I was traveling southbound on Mopac Expressway between 2222 and Enfield. I saw what at first glance appeared to be a spotlight shining onto a low cloud. However, there was not the typical 'beam' that one sees and the light was made up of several (at least 5) separate points of light arranged in a triangle. The points broke apart and meandered across the underside of the cloud in what appeared to be a random pattern at abnormal velocities before reforming into the triangle. The triangle of lights then disappeared, although a single light source (faded and not as visible as before) was observed leaving the underside of the cloud before fading even further.My first reaction was that this was, like I said, a spotlight from some event shining up at the sky, but there weren't any beams and the light seemed to be emanating from the cloud rather than being a reflection. Also, the movement was too fast and random to be a bunch of ground spotlights. There wasn't any noise that I could hear (driving with windows up). The event lasted from when I first noticed it at 9:40 pm until 9:45 pm. I did not observe any aircraft in the area.