Three metres in diameter it floated at waist height with no visible means of support, its surface mirror-smooth and perfectly reflective. How did it work? (Magnets was my first guess.) Who made it? And why did they put it here, of all places, in the corner of a scruffy provincial park?

There was panic at first. Was it a landing craft? Was it radioactive? Poisonous?

I was walking the dog at the time. I thought there was something in my eye, a little circle where the colours were right but the shapes were wrong. Up close it was like looking at the back of a huge spoon.

By teatime it was surrounded by crime tape and operatives in hazmat suits. The following morning it was declared safe and suddenly the biggest problem was crowd control.

We felt special in a way that we had never done before. We saw our reflections and we looked different. I was interviewed by a TV crew from China.

In week four a drunk woman climbed onto it, fell off and broke her pelvis, so the council put up a safety cordon. By week five the park was largely mud and pizza boxes. Bored kids upended the Portaloos. Someone spray-painted the sphere with a large cock and balls.

It began to move during week six (which scuppered my magnet theory). A distracted motorist ploughed into Sainsbury’s as it crossed the High Street, and the 2:47 to Coventry was delayed. It circled the Bridewell flats for a good hour.

We never did get any answers. The crowds drifted away. The grass grew back. It passes overhead these days and some people don’t even look up.

The dog and I find it sometimes on a Sunday morning hovering over the water treatment plant and I always think it looks sad.

Title: The Sphere
Materials: Unknown
Mark Haddon is a writer and artist