PLANCK STARS is a five-member Japanese idol girl group from Hiroshima. They made their debut in 2018 and reached mainstream success in 2021. Their music is a mix of Rock and electronic dance music.
The concept behind them is described as "free-spirited delinquents." The name sounds like "pranksters", which describes many controversies in which the group has been involved. Their antics have ranged from a member exiting the stage mid-song to buy a churro, to releasing 300 live crickets in the audience. Members have also hammered the ceiling of a venue; slept on stage; stepped on a fan; thrown ink and soy sauce at the audience; spit watermelon seeds into a fan's mouth; and made a fan drink detergent.
The concept was born from a desire to go against Japanese idol girl groups culture, who tend to face a lot of boundaries on who they can be and how they must act in public. Members perform wearing extravagant clothing, sing foulmouthed lyrics, and even have a monkey and a dog as official members.