When Dragon Ball’s Earth was on the precipice of total annihilation, Gohan was the only hero who could save the world and defeat the ultimate evil that threatened the planet–and in doing so, Gohan nearly doomed the entire universe.
During Dragon Ball Z’s Cell Saga, the villainous bio-android traveled back in time to the present day in order to absorb Androids 17 and 18 and unlock his perfect form–a dark mission he successfully completes. However, Cell wasn’t satisfied with simply achieving his perfect form, he wanted to give it a proverbial test drive. Once at full power, Cell decided to hold a tournament dubbed the Cell Games where Earth’s strongest fighters would challenge him one at a time, and if he defeated all of them, then Cell would destroy the world. Before the tournament began, the Z-Fighters took turns training inside the Hyperbolic Time Chamber, allowing them to fit a year’s worth of training in a single day. Within that time, Gohan was successful in unlocking not just Super Saiyan 1, but also Super Saiyan 2 (the first Saiyan in known history to do so)–and with that power, Gohan obliterated Cell and cemented his spot as the most powerful fighter in the world.
In Dragon Ball chapter 449 by Akira Toriyama, the villainous sorcerer, Babidi, is trying to awaken Majin Buu from his stasis. To do that, Babidi has to charge Buu’s ‘egg’ with energy that had been stolen from some of Earth’s strongest fighters–and one of those fighters was none other than Gohan. During that year’s World Martial Arts Tournament, Gohan was goaded into powering up to Super Saiyan 2 only for one of Babidi’s minions to steal that power from him using one of the sorcerer’s mystical devices. When Babidi transferred that power into Buu’s stasis pod, it is revealed that Gohan’s power alone gave Buu most of the power he needed in order to awaken.
Gohan’s Immense Power Contributed to Buu’s Awakening
While Gohan’s SSJ2 power-up was integral to defeating Cell, the power he amassed contributed to the awakening of something far worse. Majin Buu is the ultimate force of destruction and is nearly invulnerable to attack. Unlike Cell, whose powers and abilities were stolen from past Dragon Ball fighters including Goku, Piccolo, and Frieza, Majin Buu is naturally strong on a god-like level. Before he was put in stasis, Majin Buu absorbed a god known as the Lord of Lords–an entity that was strong enough to defeat the world-devouring Moro–which confirms Majin Buu’s unparalleled strength even before he stepped into battle with one of the Z-Fighters. Cell can destroy a planet with a single attack, sure, but Buu can destroy a god with a single attack, so there’s really no comparison.
Based on what Gohan’s power was eventually used for–that being awakening the god-tier Majin Buu–it seems like becoming powerful enough to beat Cell wasn’t worth it if it meant that later he’d unwittingly be handing that power over to the much deadlier Buu. However, during the Cell Saga, Gohan had no choice as Cell would have obliterated the planet if he had done nothing. Therefore, by becoming powerful enough to reach Super Saiyan 2 and using that power to save the world, Gohan nearly destroyed the Dragon Ball universe–because if Majin Buu wasn’t stopped, that’s exactly what he would have done, and Gohan’s power would have been the key to that ultimate destruction.