There was a school play where an actor forgot his lines. Instead of panicking, he started making up the most hilarious lines on the spot. The whole audience was in stitches. It was a great example of how mistakes can turn into something really funny at school.
Nezuko is initially 12 years old in the manga. As the story unfolds, her age doesn't change significantly in a traditional sense, but her character development is quite remarkable.
One funny moment is when Spiderman tries to imitate other superheroes' poses and fails spectacularly. Also, when he has comical misunderstandings with villains.
Once, my cat chased its own tail for a whole five minutes. It was so confused but also extremely hilarious. It spun around and around until it finally got dizzy and just plopped down on the floor.