Bowsette, is an anthropomorphized genderbend version of the Bowser caused by the effects of the Super Crown power up. She was inside one of the chests Mario had to open. After the chest was opened, she stepped out of it and laughed. Then she started luring Mario by pointing out how pointless it is for him to keep saving the princess Peach over and over if she (Bowsette) can give him everything he wants. Mario started walking towards her as she says to him to come closer, but suddenly he grabbed her tail. In pain, she said to him not to grab her tail like that because she is sensitive, but Mario started swirling her in the air before launching her through the roof. Bowsette continued flying to the sky, while screaming, and transformed into Bowser moments before she flew out of the sight.
“Hahahahahahaha. Are you sure you want these chests? What's the point to keep saving the princess over and over if I can give you everything you want?"~ Bowsette