Complex sentence: During the credits, Jack is back in his home on Long Island, and, with Mr. Jinx, the family's cat, watches a video of Greg on YouTube in which Greg roasts Jack at the Sustengo conference.
Split into simpler sentences: During the credits, Jack is back in his home on Long Island. With Mr. Jinx, the family's cat, Jack watches a video of Greg on YouTube in which Greg mocks him at the Sustengo conference.