When you give a boy finger paint and one of the colors is green, he will have a green finger.
And that green finger will soon be a green hand.
And then he will realize his hands sort of resemble The Hulk’s hands.
So he will keep painting himself green.
And soon both of his arms are entirely green.
And he will be convinced that he is now The Hulk.
If you give a boy finger paint, he will turn into The Hulk.