Poligraf Poligrafovich Sharikov is a fictional character from the novella "Heart of a Dog" written by Mikhail Bulgakov. He is a stray dog who undergoes a transformation into a human after a scientist, Professor Preobrazhensky, conducts an experiment involving a human organ transplant. This transformation leads to a series of comedic and chaotic events that explore themes of identity and morality. As a human, Sharikov embodies the worst traits of both dogs and humans, displaying a lack of social etiquette and a crude demeanor. His character serves as a critique of the social changes occurring in Soviet Russia during the early 20th century, highlighting the complexities of human nature and the consequences of scientific experimentation.