- Fan Nickname:
- "Shadow Peach" for Peach while possessed by the Shadow Queen.
- For the longest time, in order to help differentiate this game's Yoshi partner from the main series green Yoshi character, fans called him "Yoshi Kid." In Super Smash Bros. for Nintendo 3DS and Wii U he was finally given a (probably) official name: Mini-Yoshi.
- "Paper Luigi: The Marvelous Compass" for a hypothetical game based on Luigi's adventure in the Waffle Kingdom.
- Keep Circulating the Tapes: As of the release of the Nintendo Switch, this game is the only one in the Paper Mario series - and, for that matter, the only Mario RPG - that can't be played on eighth generation systems. note
- Name's the Same:
- Twilight Town shares the name and "always at dusk" property of another Twilight Town. Mario's version is a bit creepier, though, and don't expect to meet Roxas.
- Don't expect to find any Pokémon in Petalburg. You will, however, find Sun and Moon Stones nearby.
- This General White isn't a member of the Red Ribbon Army.
- Technology Marches On: During Chapter 4, you can see a group of crows talk about how their friend got blazing fast internet speeds at 100 Mbps. Nowadays, 100 Mbps is somewhat common and is still fast on its own, but back in 2004 when the game was launched, general internet users would not have speeds anywhere near 100 Mbps.
- Urban Legend of Zelda: A particularly nasty example crept into the fandom surrounding TTYD based on faulty information that was long present on the Super Mario Wiki, wherein a user claimed to be in possession of a supposed pre-release build of the game called "beta 9" which contained a number of differences that read like fantastic fanfiction, such as an optional fight against Prince Mush, an optional fight with Rocko Pianta accessed from the Trouble Center, made-up enemies such as Burning Bills and Rusty Koopatrols, and a rematch with the Shadow Sirens in Chapter 6 with the implication that the Sirens were responsible for summoning Smorg. Many users were skeptical of the claims, but the information was allowed to stay on the page because the user in question was a wiki bureaucrat at the time. When the user's copy of "beta 9" supposedly underwent bit rot and failed (conveniently enough, before its owner could produce any pictures to substantiate his claims), the information was unceremoniously removed the page, but not before many saw it and mistook it for legitimate information. Because data which can be traced back to the very beginning of development can be found on the disc of the retail release of TTYD, but no leftovers from the supposed features that existed in "beta 9" exist in the retail release (besides data for two other fights with the Shadow Sirens, presumably meant for Chapters 4 and 6), the "beta 9" myth can be considered thoroughly debunked. However, the various claims the user made about supposed pre-release features of TTYD have continued to be spread around as pervasive pieces of misinformation.
- What Could Have Been:
- All of the partners from the original were going to have cameos, but were scrapped bar Parakarry's at the beginning and Lady Bow in Poshley Heights. Their sprites can still be found in the game's data files.
- Admiral Bobbery had a different design that made him look like a soldier instead of a sailor.◊
- The kiosk demo of the game once playable in GameCube displays at stores is a snapshot of What Could Have Been with the game's English localization. There are some very minor dialogue differences, the Dull Bones are referred to as "Koopa Skeletons", and the X-Nauts were originally called "Boomer Gangers".
- Luigi had a Spinia partner that was abandoned a month before the game was completed. One design was based on a hamburger while the other was based on an ice cream cone.
Trivia / Paper Mario: The Thousand-Year Door