Paranormal disappearance?

When I was about 9 I was invited to go out for a day with my pal and his parents. They bought him a small ball with a long elastic, attached to a heavy weight. The weight was shaped like a flying saucer and was about 10" across. and made of tin. It was full of concrete for the weight, and very brightly coloured. There were two bats with it. After about 15 minutes, the elastic broke and we lost the ball. My pal was going the throw the base away but I asked for it as I was fascinated by the colours. When we got home, I went straight to the toilet. I sat there on the loo and had the base in front of me. I was holding it like a steering wheel. Just like a kid of 9, I was making all the tyre screech noises as I drove my imaginary car. It was that heavy that it slipped from my hand and fell to the floor with a thump. I heard it roll to the back of the toilet, then all was quiet. I finished with the loo but when I looked, it was not there. I called my granddad in and told him what Had happened. He thought I had dropped it in the loo but I told him how big it was and told him that it hit the floor in front of me. The toilet was only about 3' x 4' and yet that weight was never seen again. Although it was a bit silly, my granddad looked for it several times in a tiny room and so did I. He had no time for paranormal but he had heard the thump when I dropped it so this one had him beat. I know now, that this is a common phenomenon but it is strange when it happens to you.