* If the deleted dream sequence is of any indication [[spoiler:the Giant is one of many machines sent out across the universe to singlehandedly obliterate ''entire planets'' or, worse yet, may have already done such atrocities in the past.]]
** Extra FridgeHorror in that the other robots might ''still be out there''. And they might find Earth. And not be as friendly as the title character.
** Given that the reason the Giant is good is due to AmnesiacDissonance after hitting his head, as well as his friendship with Hogarth... [[spoiler: how do we know that he ''[[AlternateCharacterInterpretation wasn't]]'' returned to [[KillEmAll factory settings]] and his memory wiped, after he was hit by the nuke? OhCrap.]]
* The Iron Giant's transformation.
** The enraged scream he makes during that is just as disturbing. Once you've enraged him, may God have mercy on your soul.
* Mansley [[spoiler:chloroforming Hogarth.]] It comes out of nowhere, and it's [[WouldHurtAChild downright cruel.]]
** Even worse is his MoralEventHorizon shortly before that. Up until this point, Mansley has been somewhat of a bumbler, and a lot of fun to watch as he repeatedly fails to catch the Giant. [[spoiler: And then he very calmly threatens to make Hogarth's life such a living hell that he'd eventually be taken away from his mother if he doesn't reveal where the Giant is hiding.]] The worst part is the quiet, gleefully sadistic tone he's speaking in the whole time- he is perfectly capable (and willing) to follow through on any threat he makes, and he loves it.
* The Iron Giant's first appearance at the power plant.
* The bit from the old horror movie Hogarth watches where the mutant brain is presumably eating the man's head.
* The very first time we see the Giant... or rather, much like [[VideoGame/TheLegendOfZeldaOcarinaOfTime Ganon]], we don't see him at all, but instead all we see is a towering silhouette outlined by a flash of lightning... and [[GlowingMechanicalEyes a pair of unblinking eyes shining out from the darkness]].
* That moment in the woods after the deer has been shot that the Giant notices the guns and [[RedEyesTakeWarning his eyes turn into red pinpricks]]. And we immediately get the hint about what he truly is.