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.
It could also be related to a prophecy or a pre - determined fate in the fanfic's plot. There might be some kind of dark prophecy that says Kawaki has to kill Naruto to prevent a greater evil. Or perhaps Kawaki is being controlled by an external force that has a vendetta against Naruto and uses Kawaki as a tool to carry out the murder.
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.
One common theme is friendship. Writers often explore how Himawari and Kawaki, who come from different backgrounds, form a bond of friendship. Another theme is growth. They both grow as characters, learning from each other.
Kawaki makes his appearance in Boruto manga at a specific point, but I can't recall exactly. You might want to check the official manga sources for the precise chapter.
Once, my grandpa was looking for his glasses everywhere. He was turning the house upside down. After half an hour of frantic searching, he found them on his head. It was hilarious.
Once I was at a party and I was so excited to try this new dance move I'd just learned. But when I started, I slipped on a small puddle of spilled drink and landed right on my butt. Everyone stopped and stared for a moment, then burst out laughing, including me. It was so embarrassing yet funny at the same time.
There was a game where a Techies player set up a whole bunch of mines in the wrong area. Instead of trapping the enemy, he ended up blocking his own team's path to retreat. As the enemies chased them, his teammates were blowing up left and right on their own mines. It was really a comical sight. Everyone in the game was laughing about it, even the Techies player himself after realizing what he had done.