Complex sentence: Due to its unusual, star-shaped silhouette and when lots of meteors illuminate the night sky, sightings of Cleffa strangely increase, some people believe that it came to the Pokémon world on a meteor.
Split into simpler sentences: Due to its unusual, star-shaped silhouette and when lots of meteors illuminate the night sky, sightings of Cleffa strangely increase. Some people believe that it came to the Pokémon world on a meteor.