Sometimes the best moments are made up on the spot! For this list, were looking at ad-libbed, improvised, and unscripted moments in the Marvel Cinematic Universe. Our countdown includes Avengers: Endgame, Thor: Ragnarok, Captain America: The First Avenger, and more! Whats YOUR favorite unscripted MCU moment? Let us know in the comments!Watch more great Marvel videos here: Top 20 Most Rewatched Marvel Movie Scenes: