The legendary shield was created by out of a strange alloy of Vibranium, a rare metal found only in the African country of Wakanda — but more importantly, it’s virtually indestructible. So how does the weapon get cracked like this in the movie?
One potential clue: The Scarlet Witch (Elizabeth Olsen) is right there, so maybe her probability-altering hexes made it more likely the shield could be damaged? We don’t know which version of the Witch’s powers will be used in the movie, it could happen.
Another possibility? Well, in the comics, Thanos broke the shield by bringing to bear the power of the Infinity Gauntlet — and we know Thanos (Josh Brolin) is going to figure into the movie somehow.