THE FOLLOWING DRIVERS WILL ENTER THE REALMS

In Super Mario Galaxy 2, help features such as the Cosmic Spirit and the Hint TVs are coded to disappear when playing as Luigi.

The technical explanation for this is most likely that playing as Luigi changes the controls and the developers did not want to record two separate sets of inputs for the help functions, instead choosing to not make these features available at all when playing as him.

However, a humorous side effect of this is that in-universe, this makes it appear as though no one simply wants to help Luigi.

Extremely rare officially licensed 1996 figurine of Punchinello from Super Mario RPG, from Japan.

In the Toy Time Galaxy in Super Mario Galaxy, a planetoid exists that, unlike nearly every other object in that galaxy, is not a clearly identifiable toy or food-related item. The official guide for the game also does not identify it, merely calling it "a planetoid with a screw".

The internal name for that planetoid in the game's code is "RayGunPlanet". This suggests that it was intended to resemble some manner of vintage ray gun toy, though which part of the planetoid is supposed to represent which part of the toy is not entirely clear.

Normally, whenever a board game finishes in a Mario Party game, there are clear rankings among the contestants as they are first ranked by stars, and for equal star values, ranked within those by coins. However, rarely, two players may have both matching star and coin totals, necessitating a tiebreaker which takes the form of a die roll.

Normally, if such a die roll is performed to determine the winner of a game, the winner of the die roll becomes 1st and the loser becomes 2nd. However, a code oversight in the 8-player mode of Mario Party 7 results in the losing team of the die roll being made 4th instead.

Note how the Toad/Daisy team and the Yoshi/Boo team have the same numbers of stars and coins, but due to losing the tiebreaker, Yoshi and Boo were placed lower than the other two teams, which had fewer stars.

In Paper Mario, the Peach segment in the intermission between Chapter 5 and Chapter 6 features a quiz show called the 64th Trivia Quiz-Off, where Peach competes against two Koopatrols, Spiky Tom (on the purple stand) and Spiky John (on the blue stand).

The quiz is deliberately very simple and most players would be able to win even on the first playthrough of the game, which gets Peach a Jammin' Jelly item as a prize. However, there are three other outcomes that can occur if the player does not win.

Top row: if the player does nothing, Spiky Tom will give a few correct answers and win. He will be shown getting the Jammin' Jelly.

Middle row: by strategically answering only some questions, it is possible for the player to tie with Spiky Tom. In this case, the Hammer Bro host will take the prize for himself.

Bottom row: by instantly buzzing in on every question and giving only wrong answers, Peach can prevent not just herself, but any of the contestants from getting any points whatsoever, which also results in the Hammer Bro taking the prize.

Note that Spiky John can never win, or tie with Peach for most points. He is specifically programmed to lose.

In Super Mario Sunshine, it is possible for many NPCs that are not usually supposed to sink into goop to actually be made to sink into goop during regular gameplay. Whenever Mario passes through goop, he leaves a small trail of it after himself. The trail can be accumulated as passing through it lets Mario extend it by a few more steps, allowing Mario to (very slowly) take the goop nearly anywhere on the map by doing it repeatedly.

As such, NPCs normally standing outside of goop can be made to sink into it by having Mario bring the goop to them. They all have animations for sinking into goop, even if those would not normally be seen.

However, despite having an animation for sinking into goop, as seen above, Toadsworth is actually coded to be completely immune to goop. Unlike the majority of NPCs, no matter how much goop is around Toadsworth, he will never sink into it, making the above animation entirely unused.

In Super Mario RPG, on the second visit to Bowser's Keep, Mario must pass through 4 out of 6 randomly shuffled areas, which include two "action rooms", two "battle rooms", and two "puzzle rooms".

One of the action rooms includes a segment with rotating platforms above lava. Examining this area in the game's code reveals that it has a copy of Mallow floating in the void on the left side of the room (near the left edge of the image). What Mallow is doing here is unknown.

Interestingly, this Mallow is programmed to do only one thing upon loading: unload. As such, he exists only for one frame before disappearing again.

In the first mission of Slipsand Galaxy in Super Mario Galaxy 2, Mario or Luigi must slide down an extremely long slope. After they begin sliding, cylindrical Thwomp-like enemies called Rhomps appear from behind and attempt to squash them by rolling over them.

If the player is playing as Luigi and performs an extremely precise long jump just as Luigi is about to be rolled over by a Rhomp, Luigi will gain immense speed that will catapult him into the air as seen in the footage.

Unfortunately, there is no way for the player to slow down Luigi at that point, so that after flying far enough to exit the regular gameplay area, Luigi will leave the boundaries of the galaxy, and die.

Officially licensed 1996 Yoshi's Island stamp of a Burt enemy, from Japan.

Officially licensed 2002 Super Mario Sunshine figurine of Red Toad, from Japan.

In Super Mario World, the P-Balloon item actually remains loaded for the entirety of the time that Mario is in his P-Balloon power-up state, as it contains the relevant code that determines how Mario moves while in that state.

The way this is accomplished internally is simply by making Mario hold the P-Balloon for the duration of the power-up, but making the item itself invisible. The above screenshot shows what the scene would look like if the P-Balloon were visible.

This also explains why Mario cannot hold items in this state. Instead of him being specifically coded to not be able to hold items while in balloon form, he cannot hold them simply because he is already holding an item: the invisible P-Balloon itself. As such, this is less of an intentional limitation of the item and more of a side effect of how it is implemented internally.