Why is that there are fish fossils on Mars?

The Martians were a peaceful people who lived in harmony with their planet. They were content to stay in their own solar system, and had no desire to explore beyond it. But one day, a strange object appeared in the sky. It was huge and bright, and it seemed to be headed straight for Mars.

The Martians were terrified, and they did everything they could to try to stop the object. But it was…