Stanisława Popielska (born c. 1893) most well known as Stanisława P. was a Polish spiritualist medium who was alleged to have produced ectoplasm and the psychokinetic movement of objects. In 1913, Stanisława was investigated by the psychical researcher Albert von Schrenck-Notzing. During the séances a number of flashlight photographs were taken, he published a book on the subject of materializations and declared her ectoplasm to be genuine. Schrenck-Notzing's experiments with the medium were criticized for their poor controls and he was accused by scientists of being the victim of fraud after his book was published.