Sometimes in children's stories there [STRIKE]happens to be[/STRIKE] is an old fat man who tells [STRIKE]them (children) [/STRIKE] the children various stories. Sometimes he gets angry in a funny childish way, hides his face, his face becomes pinkish and he looks [STRIKE]so[/STRIKE] very childish.
How should I describe that anger?
I wasn't sure if you were talking about a very specific children's story that you have read, or about stories in general. I have made amendments above assuming the latter. If the former is the case, then it should start "In a children's story I have read, there is an.........."
However, as far as your actual question is concerned, I can't actually think of a word. Is he actually angry? Is he playing? I don't really see how you can get angry in a childish way, and I don't understand why he would hide his face!
When children get angry, it can sometimes be called petulant. This is when they maybe stamp their foot, stick out their bottom lip and sulk, but it's not necessarily angry, they are just being difficult!