In the Dragon Ball franchise, Majin Buu is one of the most complicated characters. Created by a wizard in an attempt to take over the universe, he's existed as a lovable pink blob, one of the series' most powerful villains, and even a human character, all depending on which Buu you are dealing with at the moment. At times, it's hard to tell if you are talking about the same character because it's hard to tell if they even are the same character.
Whether he's annihilating the human race or bringing puppies back to life, there's a lot you can say and think about Buu. He's also the subject of one of the most famous puns in the anime: take the names of the wizards, Bibidi and Babidi, and add Buu's name and you have a shout-out to Disney's Cinderella.
That said, there's still a lot that can be confusing about Buu. Let's take a look at some questions fans might have about him. And since questions can arise at any part of a story, spoilers abound.
10 Couldn't 18 Fight Him?
At this point in the story, Android 18 had unlimited ki, and possibly could have managed to pick up a good fight against Buu, yet she leaves with her daughter for safety. Now, unlimited energy doesn't necessarily mean that she would have had the power to take him down, especially considering what happened when she fought Cell, but she could have helped weaken him in the overall fight. And Marron may be her most important priority, it would probably be safer for the world at large, including her daughter, if the people fighting the bad guys were significantly weaker than her.
9 The Human Extinction Attack
When Super Buu uses his Human Extinction Attack, he claims that he wiped out the entire population of the planet Earth. It's already established that some people were spared due to a variety of reasons: whether it's dodging the attack or due to Good Buu's intervention. But in the world of Dragon Ball, there are plenty of characters in this universe that aren't explicitly human. And not just androids, monsters, and extraterrestrials. Even back in the first season, there were plenty of anthropomorphic animals. This brings up a few questions: were any being on Earth inhuman enough to survive the attack or is the name a little misleading?
8 Priorities Concerning Buu
When Goku and Vegeta plan to get Buu to absorb them in order to rescue other people he had absorbed, it begs the question: are the characters are making too much work for themselves?
The Dragon Balls can revive people who have been killed under a shared circumstance, meaning that just killing Buu should be the main priority, since anyone killed because of his existence can just be wished back to life. It's possible they're concerned about such a wish also bringing back Buu, but the Dragon Balls shouldn't have power over someone stronger than them.
7 Too Many Buu's
Evil Buu is formed in part from Fat Buu, later becoming known as Good Buu or Mr. Buu, expelling the evil within him. He initially becomes weaker, only for him to be absorbed by his evil counterpart and become Super Buu. Once the original Buu is freed, he becomes Kid Buu, who turns out to be the original. That's not getting into the fact that one of them eventually generated into a human incarnation named Uub, who later fuses with Buu to become Majuub. There's also a Buff Buu in there somewhere. After a time, it seems like there are too many Buu's than there needs to be, with some Buu's coming to be out of nowhere.
6 Co-existing Buu's
Relating to the above, if Buu exists in different incarnations at the same time, how distinct are the entities? Piccolo and Kami were also good and evil counterparts to each other. are treated as sharing the same life-force, to the point of one fading away if the other one dies. This begs the question as to how Buu seems to have become able to co-exist with his other identities without them necessarily impacting each other's life-force. Is this just a special quirk Buu has?
5 The Super Spirit Bomb
When the Super Spirit Bomb is used against Buu, all the people of earth need to raise their hands and offer up their energy to fight Buu. Android 18, as previously established, has unlimited ki and characters like Gohan have proven themselves to be more than powerful enough to take on Buu, and so the attack should have already been enough without involving other people. Added to that, it was previously shown that the spirit bomb could be conducted summoning energy from mere surroundings. While the attack was eventually powerful enough to defeat Kid Buu, albeit not without attempting to reflect it back at an exhausted Goku, it begs the question if such power was really needed.
4 Buu's Bones
Buu seems to be made up of a pink goo-like substance, but other times it seems that there is more to Buu's inner workings. Buu can be seen cracking his neck, suggesting that he has neck bones.
And this is just the start of things. He is also clearly able to stand upright, but is that proof that he has a spine underneath or is there something else going on? After all, the reason that snakes can lift up their heads, while worms generally cannot, is because they have bones.
3 Buu's Cape
Good Buu is shown wearing a cape, but it seems to actually be part of his body. After all, it disappears and regenerates when switching back and forth between forms. It's also likely a holdover from absorbing the Grand Supreme Kai. However, there have also been times when Buu has been shown to be able to take off his cape. Is it really a part of him or not?
2 Buu Killing Supreme Kais
Buu had killed two Supreme Kais and they seemed to have stayed that way. Being heavenly being, Kais were otherwise shown to practically survive death, even keeping their bodies, and the only change is that they now have halos. King Yemma doesn't even have power over them. And the only way to truly destroy them was to destroy Gods of Destruction. How did Buu become a loophole to this issue, finding a way of erasing a Kai from existence?
1 Babidi Underestimating Him
The evil warlock Babidi, son of Bibidi, was the one who sought to revive Buu, his father's creation. Babidi is shown to be able to use his magic to manipulate and control people and he also plans on using Buu to terrorize the Earth. Yet, he never thinks of using his powers to control Buu to ensure he doesn't rebel. Even if he didn't think he needed the security, it still feels like he wasted the chance to have direct control over Buu's powers. And even if Buu was somehow immune, it doesn't make sense that he wouldn't try. He wasn't afraid of Buu and Babidi severely underestimates the possibility of Buu betraying him; in fact, the wizard ultimately lost his life because he didn't realize the fatal consequences of pushing Buu too far.