For all his wisecracks and mischief, the origin story of Rocket Raccoon in the Marvel Cinematic Universe is a harrowing one. In Guardians of the Galaxy Vol. 3, Rocket’s history is revealed to involve everything from animal cruelty, to unethical science practices, revenge, and tragic loss. It’s a story that James Gunn, an unabashed animal rights activist who often weaves his politics into his films, has wanted to tell for a long time. Less than a year after his first Guardians of the Galaxy became a sleeper hit, the writer/director revealed in a March 2015 Facebook Q&A one of his...