The Iron Giant is a beloved animation classic, but an addition made by the Signature Edition may have actually brought attention to a dark plot hole in the film. The movie is a good bit of wholesome family fun, featuring the time-honored formula of "A boy and his..." In a similar vein to the '80s juggernaut that was E.T Extraterrestial, this one features a friend from space, but with a far less innocent origin. Despite learning about the titular Iron Giant's true capabilities around the film's climax, audiences are treated to a feel-good, optimistic ending. Except there's still the question of the giant's origin and why he came to Earth that goes unexplained in the original cut.
When the Signature Edition of the film came out, it added a couple of deleted scenes back to the movie. One of which further elaborated upon the origin of the giant through a dream sequence. In this particular scene, the giant has a flashback that manifests as a nightmare, showing legions of others like him, decimating alien worlds. The scene answered a number of questions about the Iron Giant, where he came from, and what his original objective was.
It's the updated information around the Iron Giant's origin, however, that paints a grim picture for the future of Earth. If the Iron Giant really is part of a larger force, what's stopping that army of identical models from coming to wreak havoc? Were that to happen, the charmingly optimistic ending of the first film actually could be spun in a much more ominous direction and likely spell doom for the little blue planet.
Humanity Couldn't Survive An Iron Giant Invasion
The Iron Giant is clear that the title character is only benevolent due to a specific set of circumstances that would likely have to be perfectly replicated in order to get the Iron Giant army to adopt the same nature. While Hogarth puts forward the idea early on that the bump on the noggin was enough to change the Giant's nature, this was later disproven. It merely gave him amnesia of his cause. It was Hogarth's friendship that ultimately contributed to the Giant not eventually becoming the death machine he was always intended to be. This is made abundantly clear when the Giant believes Hogarth to be dead and reverts to his destroyer mode, only to revert back when he learns that Hogarth is alive and well.
With the new scenes from the Signature Edition making it clear that the Giant isn't the only one of his kind, it presents the idea that more of these metal titans could land on Earth at any time. It's never made clear how the planets are chosen or why he's alone. It's therefore entirely possible that any alien entity capable of creating this advanced army of space-flight-capable war machines would have a means of tracking their creations. Whether the Giant got lost or was simply a scout, it's very possible his mere presence could mean more of them could be on the way. With an entire army of Iron Giants to contend with, it's very likely humanity could simply be overwhelmed.
Perhaps the thing that would doom humanity the most, however, would be the inability to hurt them at all. The movie takes place in the 1950s. At the climax of the film, the Giant seemingly sacrifices himself to save innocent people from an atomic bomb. However, the film's conclusion reveals that the Giant not only survived the encounter but is reassembling himself. Even worse, there's not a singe-mark to be seen on his metal frame, meaning that the most powerful weapon available to mankind at that time wouldn't be able to reliably hurt an Iron Giant army. In the end, humanity wouldn't be able to stand up to an Iron Giant invasion, so perhaps it's a good thing for them that there is no sequel.
