Tensie's essence was planted inside the tennis racket of a girl named Katie. Once Katie's energy reached its highest point, Tensie appeared from the tennis racket, draining her energy for the Negaverse. She trapped Sailor Moon in a tennis ball and threw her around the court, but was stopped by Tuxedo Mask. After being stunned by Tuxedo Mask, Tensie was destroyed by Sailor Moon using Moon Tiara Magic.
Her name is derived from the word tennis, as tennis seems to be her theme, and she was implanted in a tennis racket.