Princess Sissy (プリンセス・シシー) is a character in Power Instinct Matrimelee, serving as the game's final boss. In the Neo Geo console version of the game, she could be accessed by holding all four buttons down when selecting the character and before the Vs. screen. She reappeared in Shin Goketsuji Ichizoku: Bonnou no Kaihou, but this time was no longer the final boss and the only way she could be fought as an opponent was through the game's Mission Mode, or the Training Mode.