Crayon Shin-chan Movie 25: Shin-chan Shuurai! Uchuujin Shiriri

A small alien named Shiriri suddenly appears at the Nohara home and accidentally blasts Hiroshi and Misae with a ray that turns them into children. The only person who can restore them is Shiriri's father, so Shinnosuke and his newly youthful parents set off across Japan with the alien concealed from anyone who might discover him.

What begins as a bizarre family trip soon reveals a much larger plan involving Shiriri's father and humanity itself. As the journey draws Shinnosuke and Shiriri closer, the boy must help his new friend question the orders he has always obeyed while the Noharas race to recover their normal lives.