Dragon Ball: That Time I Got Reincarnated as Yamcha! (ドラゴンボール外伝 転生したらヤムチャだった件 Doragon Bōru Gaiden: Tensei-shitara Yamucha Datta Ken) is a spin-off manga written and by Dragon Garow Lee, it is released in Shueisha's Shonen Jump Plus digital manga magazine.
In the real world, an ordinary Japanese high school student is on his way to a Dragon Ball event and makes a detour to hit on a cute girl. Unfortunately, he meets with an unfortunate and fatal accident before he reaches her and, to his great surprise, wakes up in the Dragon Ball universe as Yamcha! Being a Dragon Ball fan, he knows exactly what misery awaits him as Yamcha, so he takes matters into his own hands and vows to make Yamcha the strongest Dragon Ball character ever!
The work contains examples of:
- Adaptational Badass: This trope is invoked for Yamcha. As the title suggests, the main character is an ordinary teenager who dies and gets reincarnated as Yamcha. Being well aware of what happens to Yamcha, he decides to train hard and change that. And he succeeds. By the time the Saiyans arrive, his power level is over 10,000, letting him easily wipe out all the Saibamen singlehanded and defeat Nappa on his own. Even though he's not quite as strong as Vegeta, he's still powerful enough to team up with Goku to defeat him.
- This also happens with Chiaotzu, since he's another real-worlder reincarnated into the Dragon Ball universe. The main difference is that he's been through multiple loops and by this point he wants to take over.
- Alternate Timeline: One in which Yamcha manages to stay on par with the heroes in the early parts of the series and avoid his embarrassing death that befell him in the Saiyan Saga of Dragon Ball Z. This causes the timeline to diverge further because of this, such as causing all the Z fighters that fought Nappa and Vegeta to survive that fight and accompany Krillin, Gohan, and Goku to Namek.
- Art Shift: Several, the most notable being the shift from the "real-world" introduction to that of Toriyama's Dragon Ball, with the former being more realistic. Additionally, the art in the Dragon World also shifts to align with Toriyama's own art style at the shown points in the story: the opening is more rounded like in the Pilaf Arc, for example.
- Beyond the Impossible: Played for Laughs with a piece of artwork that shows "Yamcha" punching out Beerus. No such thing happens in the manga, artist Dragon Garow Lee was just having a bit of fun.
- Can't Catch Up: Played with, bordering on deconstruction. He keeps up with Goku through the Saiyan Saga but by the time Cell appears, Yamcha realizes he won't get much stronger and decides to focus on enjoying his life.
- Cosmic Chess Game: The ending reveals the entire thing was a board game between Gods of Destruction Beerus and Champa.
- Defeat Means Friendship: Averted. Yamcha and Chiaotzu end their fight peacefully when the former reminds the latter of his love of Dragon Ball.
- Fusion Dance: In the Bonus Manga, Yamcha uses his knowledge of Dragon Ball: Fusions to have Bulma invent the Metamo-Ring from that game so he can fuse with Chaiotzu. They both abandon the idea after seeing how ridiculous they look once fused.
- "Groundhog Day" Loop: As it turns out, if "Yamcha" dies, he would have to go back to the moment he reincarnated and try again. He never gets to do so since he does fine the first time around, but Oushou (the person reincarnated as Chiaotzu) has had to go through the same thing dozens of times.
- I Want My Beloved to Be Happy: The Boy's original goal is to get Bulma as a girlfriend, but once he realizes that she needs to get with Vegeta so Trunks will exist, he gives up on her.
- Know When to Fold 'Em: Despite "Yamcha"'s massively boosted power level, he knows that as an ordinary human, he's bound to fall behind. By the time the Z Fighters get to Namek he starts to hang back and let Krillin, Goku, and Gohan take point.
- Literary Allusion Title: The title references Fuse's That Time I Got Reincarnated as a Slime, particularly the idea of focusing on the growth of a character usually regarded as the lowest member of the pecking order.
- Look Behind You: Yamcha pulls this on Vegeta during the Saiyan Saga, shouting "Look, it's the God of Destruction, Beerus!" Again, it works.
- Media Transmigration: A Dragon Ball super fan reincarnates as Yamcha and uses his encylcopedic knowledge of the plot to make Yamcha more than the weak minor character that he is.
- Motive Decay: Oushou/"Chiaotzu" started off optimistic, but after going through several time loops where he was gradually left behind he got bitter and eventually decided to use the Dragon Balls to make himself ruler of the world. Thankfully "Yamcha" is able to make him realize that this would destroy the story he loves so much.
- New Life in Another World Bonus: Since the main character is a Dragon Ball fan, he goes into the Dragon World with near-encyclopedic knowledge of the lore and timeline, allowing him to visit Namek for a power-up before the Saiyans arrive, or distract Vegeta by invoking his fear of Beerus.
- No Name Given: The main character's name is never stated in the manga, leading to fans referring to him as The Boy, The Fan, or "Yamcha".
- Point of Divergence: The moment "Yamcha"'s fate changes is when he changes his mind about going with Bulma to the city, and instead goes with Goku to Kame House to train.
- Reincarnate In Another World: The main character dies in the real world and gets reincarnated as a character from the Dragon Ball universe.
- Sequence Breaking: "Yamcha" acquires some early powerups quickly be going to Namek earlier than in the original story.
- Peggy Sue: The high schooler that reincarnates as Yamcha uses his foreknowledge of Dragon Ball to strengthen himself and use as many tricks and shortcuts as possible get strong enough to avoid dying.
- There Is Another: "Yamcha" is not the only person that has been reincarnated. Chiaotzu also has been reincarnated, and is doing a lot worse.
- Throw the Dog a Bone: The whole story is essentially one for Yamcha who, ever since the Saiyan saga, been relegated as a Butt-Monkey in the series by the fans. Granted it's an unnamed high schooler in control of his body who likewise considered Yamcha as such in-universe, but decides to turn that around and go against what originally transpired.