Avengers: Infinity War is such a tightly paced movie that it's hard to think about improvisation slipping through the cracks of Marvel's master plan. But the Russo brothers's director commentary on the Blu-ray edition of Infinity War (h/t Shadow and Act) reveals that one of the movie's coolest moments came completely unexpected. SEE ALSO: 'Avengers: Infinity War' breaks $2 billion at the box office The scene occurs at the beginning of the Battle of Wakanda, where the earthbound Avengers, the Wakandan army, and the Jabari tribe join forces to fight Thanos's army of space dogs (well, that's what Rocket likes to call them). As the armies prepare to take the fight to Thanos, Winston Duke's Chief M'Baku begins a familiar war chant -- the same heard in the first challenge and later battle against Killmonger in Black Panther. Chadwick Boseman's King T'Challa follows the Jabari chant up with his own and the battle begins with the now heavily meme-ified catchphrase "Wakanda forever!"