What is "katamari"

The series is video game franchise created by Keita Takahashi and developed and published by Namco (and subsequently Bandai Namco Entertainment). The series puts players in control of a character called The Prince as he uses a ball called a katamari to roll up objects. The first title in the series was Katamari Damacy for the PlayStation 2, which became a cult classic and led to several sequels and spin-offs.