Marvel Warning: There are major spoilers ahead for "Avengers: Infinity War." When you head out to theaters to see "Avengers: Infinity War," make sure you stay until the very end of the movie. See the rest of the story at Business InsiderNOW WATCH: This incredible animation shows how humans evolved from early lifeSee Also:‘Avengers: Infinity War’ ends on a cliffhanger that will leave you devastated — here’s what it means for the sequelEverything you need to know about the Children of Thanos — the villainous crew in 'Avengers: Infinity War'The only Marvel movies you need to watch before seeing 'Avengers Infinity War'