Short answers, pulled from the story.
Professor Simon Dentith defined parody in 2000 as any cultural practice providing a relatively polemical allusive imitation of another cultural production or practice.
The Supreme Court ruled in Campbell v. Acuff-Rose Music Inc. that a rap parody of Oh Pretty Woman by 2 Live Crew constituted fair use.
Mud and Sand released in 1922 served as early parody film directed by Stan Laurel mocking Rudolph Valentino Blood and Sand.
United Kingdom legislation effective the 1st of October 2014 provided exception where fair dealing exists for purpose of parody caricature or pastiche under Section 30A of Copyright Designs and Patents Act 1988.
Aristotle identified Hegemon of Thasos as the inventor of parody in his Poetics from the second chapter fifth section.