A/N: Sorry about not updating my other story. If I even tried to put any work into continuing it right now, with all the stuff I have for school, I'd probably just drop dead from exhaustion. Here's a consolation prize.
In Ta no Kuni (The Land of Rice Paddies), a butterfly flaps its wings. A bird notices this movement, quickly swooping down to eat the butterfly. The bird rustles some leaves, drawing the attention of a handful of samurai guarding a nearby rice farm. Had they not been distracted by the bird, they would have noticed the inexperienced Oto (Sound) shinobi sneaking up on them in time to kill him. However, because they were distracted, the Oto shinobi succeeded at sneaking up on the samurai, killing them before they could react.
As a part of Orochimaru's plan to conquer Ta no Kuni, he sent out his ninja to destroy rice farms, weakening the country's economy. This particular Oto shinobi, who would have died if not for the butterfly that flapped its wings, destroyed the farm he had been assigned, before returning to Orochimaru's headquarters for further assignments. He would go on to destroy two more farms before meeting his demise, farms that would have been left unmolested if he had not been available to attack them.
After Orochimaru managed to conquer the country, he didn't bother rebuilding any of the rice farms he had destroyed. The inhabitants of the former Ta no Kuni, now Oto no Kuni (The Land of Sound), did their best to repair the damage dealt by Orochimaru's hostile takeover, but the three farms destroyed by the unnamed Oto shinobi remained abandoned.
Over the course of the next few years, the slight decrease in the production capacity of Oto no Kuni lead to a lower supply of rice than there would be otherwise, slightly raising the commodity's price across the elemental nations. Konohagakure no Sato (The Village Hidden in the Leaves) was no exception to this rise in prices.
On the day of the first stage of the Chūnin Exams, Naruto foolishly decided he wanted to try something new to eat, because maybe it'll give him superpowers. However, he was no longer earning an orphan's stipend, and had not been economically independent for long enough to really be able to manage his money, so he was nearing the limit of his budget. Had the price of rice not increased slightly, Naruto would have been able to just barely afford to purchase some sushi to try; however, because of that butterfly flapping its wings in a whole 'nother country, Naruto couldn't afford the sushi he originally wanted to buy, gave up on his food-related aspirations, and went to Ichiraku's instead.
The flora and fauna of one's stomach is a fascinating and complex ecosystem, often finely balanced based on the food and drink consumed by a person. Changing up the precise balance of nutrients present therein can throw off one's intestinal biology, having consequences on the host's gastrointestinal health. Had Naruto eaten that sushi, he would have ever so slightly upset the nutrient balance in his stomach. It would not affect him immediately, but after approximately five days, a specific species of bacteria would increase in population enough to begin producing gaseous byproducts that would require expulsion. This expulsion would be key to Naruto's victory against Kiba in the preliminary rounds of the Chūnin exams.
Without the assistance of the sushi-bacteria in his gut, Naruto lost in the Chūnin exam prelims. Without the promise of a difficult fight looming in the Chūnin exam finals, Naruto would not receive training from Jiraiya, and therefore would not learn how to summon toads.
At the finals of the Chūnin exam and during the subsequent Suna/Oto (Sand/Sound) Invasion, Sasuke would still fight Gaara, Gaara would still enter his Bijū (Tailed Beast) transformation, and Team Seven would still be tasked to find and fight him. Without his ability to summon Gamabunta to free him from Gaara's Sand Coffin, Naruto would be crushed to death in this battle.
Decades later, Akatsuki has collected all but the Kyūbi (Nine-tails), for which they have been waiting to reform after its death inside Naruto. Working together, the numerous S-ranked missing-nin successfully capture the Bijū, sealing it into the Gedō Mazō (Demonic Statue of the Outer Path) and reviving the Jūbi (Ten-tails). Without the reincarnations of Indra and Asura to fight the Jūbi, the Eye of the Moon Plan is successful, Kaguya Ōtsutsuki absorbs all of the chakra in the world, turning everyone into White Zetsu, and the world as everyone knows it is gone.
So don't let anyone tell you that butterflies are harmless. This butterfly managed to singlehandedly destroy the world.
A/N: I'm mildly annoyed, because despite there being nearly nothing objectionable in the fic, I'm still gonna have to rate it T because I mention death, and a story can only be rated K+ if there is minor violence without serious injury. Does the end of the world count as an adult theme?