According to rumors, Jack-Jack is actually going to be one of the main villains of the new film, after he finds himself hanging out with the wrong person. A certain villain is going to notice the boy in his impressionable, naïve state, and take him under his wing, manipulating him into becoming as evil as himself.
As a result, Jack-Jack might even go up against his own parents, a development that many fans apparently want to see as they believe it would make the new film even more exciting than the last, and the best possible development for the story that we could get.
While we don’t know if that’s going to happen or not, the rumor has definitely been quite prominent and has been going around for some time now.
But Brad Bird has already said that he’s juggling many ideas for the plot of the new film, so even if that really was something that he was planning, it could just have been a random idea that he wanted to implement but ended up throwing away. There’s no way to really know until the new film has been released, and right now it looks like this is going to take a while, so fans should be patient.
That’s great! I wonder if there will be a Jack-Jack Attack sequel as well.