These three ghostly girls are doing the see no evil, hear no evil, speak no evil from the three monkeys. Its kinda a a strange effect ghostly effect, that can be created with simple time laps camera.  If you set the shutter speed long enough, quickly shift positions and hold each one for a second or two, i twill capture your presence giving it a ghostly effect.  Since the camera see you there as well as moved it blends the two giving it the transparent illusion.

Three ghostly girls representing the three monkeys