In the Nintendo Switch Online version of Mario Party 3, Daisy's happy winning expression was changed to a more serene or confident one. This is the only expression that was changed. It is unknown if this is a glitch or if the developers believed it to better express her personality.

Unique Mario voice lines by Charles Martinet recorded for a 2009 soundboard on Nintendo's Australian website, including lines like "I love Australia!", "I love the propeller hat!" and "Ah, spaghetti, meatballs, and pizza pie".

In Super Mario 64, tiny slivers of exposed out-of-bounds areas will cause Mario to bonk if he collides with them. However, the exact same scenario in Super Mario Sunshine is much more cruel to Mario. Here, instead of merely bonking, Mario will break his spine.

Sound Fantasy was a cancelled SNES game that would have used the SNES Mouse to draw pictures to turn into sound, like a musical Mario Paint. A prototype of it surfaced in 2015. One of the sample images is this unique illustration of Mario that plays the Happy Birthday song.

Experimental post: The Duality of Whacka In the Switch version of Paper Mario: The Thousand-Year Door, Whacka can finally be fought, and has a suspiciously specific 108 HP. The game both offers a ridiculously simplistic explanation for this as well as a complex one steeped in Dharmic symbolism.

It is possible to beat Donkey Kong Country 2 completely pacifist using a combination of secrets and glitches, allowing no enemy or boss to be harmed. Ironically, getting the true ending destroys Crocodile Isle, killing everyone on it anyway.

When starting Donkey Kong Land, there is a 1/8 chance the game will boot in a "paranoid ducking state" where Donkey Kong will constantly look around while ducking. This is actually a fault of the random number generator, which "locks in" to a single value and fails to be random.

In the Mario Teaches Typing games, Mario never criticizes the player for underperforming and tries to be understanding and supportive. According to Charles Martinet, that was his initiative, as he felt being negative would go against the core principles of Mario's character.

Donkey Kong 64 contains unused text that would have referenced the Gold Skulltula sidequest from The Legend of Zelda: Ocarina of Time as a joke explanation for Donkey Kong not being able to do something.

Super Mario Sunshine is surprisingly more realistic than later Mario games in one specific aspect: here, Mario will start drowning if he hangs on to a ledge in such a way that water is flowing into his nose and mouth, as one would in real life.

The Switch version of Paper Mario: The Thousand-Year Door includes its own fictional language that is a cipher for English. Amusingly, the misspelled "Game Cuve" graffiti from the original version is translated into the new language... but still reads "Game Cuve" when deciphered.

In Paper Mario, Mayor Penguin is found seemingly dead, with Mario being suspected of his murder. However, if a letter is delivered to him during that time, he will get up, thank Mario, and promptly go back to being dead. Unfortunately, this cannot prove Mario's innocence.

Shigeru Miyamoto has claimed that Toad is his least favorite character in Mario Kart. Despite this, in all footage of him playing Mario Kart 8, he picked Toad every time. Whether he was joking or specifically picking a character he hates to challenge himself is unknown.

Paper Mario: The Thousand-Year Door inadvertently depicts Peach as the quickest typist in the world. She is able to type up a 126-word email in exactly 3 seconds, making her 8 times faster than the current typing speed world record.

Many games for the GameCube use only a fraction of the storage capacity of the disc. I have analyzed the data to determine what the maximum number of retail Mario games that can fit on a single disc would be, creating the Luigi & Wario + Puzzle + Rhythm Maximum Value Pack.

While Mario collects fictional gold coins in his games, Wario in Wario World collects the real-life "American Gold Eagle" official US gold bullion coins (91.67% gold).

New Super Mario Bros. Wii contains unused Hint Movies where the players play badly and then die. While these were likely recorded before the levels were changed so the inputs don't match up, it is humorous to imagine them being actual intentional hints on what not to do.

The Super Mario Sunshine debug room contains a seemingly unassuming barrel that will become extradimensional if Mario slides into it. The barrel will appear to be superimposed onto reality like a PNG badly edited into the image.

In the prototype version of Mario & Luigi: Superstar Saga, Mario and Luigi would have needed to electrocute a living mouse for all eternity to solve a puzzle. This was changed in the finished version to a toy mouse, likely due to the original being absurdly cruel.

In Super Mario Advance 2, a "pink Mario head replica" object can be created, which will sit on the ground and mimic Mario's head (except in pink). It does nothing when touched, but will give a power-up when eaten.

In Paper Mario, the Power Bounce badge's maximum number of bounces is arbitrarily capped against bosses, making Mario end the attack even with perfect inputs. Below are ways to determine if the player should feel bad about the missed input or if it was the game's fault.

Unused graphic found in the files of Mario Superstar Baseball, possibly used as a placeholder for the title screen. It features crude sketches of Mario and Luigi seemingly made in MS Paint and the text "ルイージの兄野球", which translates to "Luigi's Older Brother Baseball".

The 2026 horror point-and-click adventure game Endacopia contains unused, seemingly deliberately clashing Mario pixel art assets (often jokingly called the "So Retro" art style) in its files. These were likely used as placeholders during development.

In Mario Kart Wii, asphalt is slightly shiny, reflecting a band of light ahead of the player. This is implemented cleverly by leveraging something that the Wii is already doing, allowing it to not need to use any sort of additional lighting or post-processing.

Compilation of rare footage of the famously unsettling-looking Donkey Kong 64 decoration at the Nintendo booth at E3 1999.

Under extremely unfortunate circumstances in Super Mario 64, it is possible for Mario to look like he really should collect a star, but end up collecting a different one instead.

In WarioWare, Inc.: Mega Microgames, the player can "trust Wario" to provide a name. Most of them are insults and nicknames, but a few are regular names. It is possible that a child actually named Louie or Rufus may have gotten frightened by Wario somehow knowing his name.

In Super Paper Mario, it is possible for an enemy to die and not die at the same time, entering a glitched state of superposition. Attacking it again is not recommended; the game cannot handle the enemy's paradoxical state and crashes immediately.

Wrinkly Kong has always been wrinkly. However, for decades, her Donkey Kong Country 3 artwork was not available in a high enough resolution to see just how wrinkly she was. In 2025, Nintendo Music finally revealed it in a quality high enough to truly see the immense wrinkliness of her skin.

It is possible to use a The Legend of Zelda cartridge to unlock the world selection option in Super Mario Bros., by swapping the cartridges without turning off the NES and performing specific actions in The Legend of Zelda before swapping back.