A very bright light that moved behind a “cloud” and flew off very quickly.

I was walking home with my mum, and she pointed at this very bright light, we thought it was the moon at first but staring at it for a while it was far too small to be the moon, there was one small cloud underneath it, which was the only cloud in the sky, the light shut off and it shut from the top and bottom, and moved behind the cloud underneath which was still slightly lit, both my mum and I watched it happen and we were very confused, I carried on watching the cloud and it started to move quite slowly and then it sped up and disappeared. It just was very bright and quite small, but that could of been because it was quite far away.