The little mouse could be afraid because it was lost in a dark place and didn't know how to find its way home. Or perhaps there was a loud noise that frightened it.
Maybe the mouse looks really scary or she had a bad experience with mice before.
The reason could be that the cartoon portrays Donald Trump in a manner that triggers fear in the little girl. Maybe his actions or appearance in the cartoon are presented in a way that makes her uncomfortable and scared.
It could be that the story or plot of the cartoon is too intense for the boy. Or perhaps there's a villain that looks really threatening.
He might be afraid because he's facing a big challenge he doesn't think he can handle. Like having to perform in front of a huge crowd when he's really shy.
The cartoon dog might be afraid because it's in a new and unfamiliar environment. Or perhaps there's a mysterious figure lurking around that's making it nervous.
It could be that the environment in the cartoon was unfamiliar and threatening to the dog. Or perhaps there was a mean character that scared it.
The cat in the cartoon might be afraid because it was separated from its owner or got lost. Sometimes, just a sudden shadow or an unexpected movement can startle a cat and make it afraid.
The guy in the cartoon might be afraid because he's being chased by a villain or has heard a creepy noise. Sometimes, it's just his overactive imagination creating fear for no real reason.
The reason the cartoon mouse is running could vary. It might be scared of a predator, or it could be on a mission to deliver an important message. Or, it could simply be having a burst of energy and running around randomly for entertainment.