Kisenian  

Kisenian Blossom, キセニアン

Kisenian was a plant capable of controlling individuals (like Fiore), corrupting their pure hearts into darkness. These controlled persons would carry out Kisenians plans as they wandered across Earth. Once all resources had been depleted or destroyed, the planet would explode. Kisenian survived on the comet that once housed the planet's remains, where Fiore discovered it. After picking the flower, Fiore realized that everyone had abandoned Mamoru, causing his heart to turn dark. Eventually, Sailor Moon revealed the truth about Usagi and Mamoru's friendship, leading to Kisenians demise.