Swing it

A small, blonde-haired character in a straw hat and light dress stands beside a taller, silhouetted figure in a bright, minimalist room, then the scene cuts to the character sitting on a bench with red markings on her legs, followed by a rapid sequence of her being duplicated and moving with a red object in her mouth, then a close-up of her face with a wide, unsettling grin, and finally a blurred image of the taller figure falling against a blue background.