Internal Clock

The Internal Clock is a scrapped mechanism that can be found in earlier builds of Super Mario 64, as well as personalized copies, first documented by Youtuber BlackJoystick. The Internal Clock can change the game to make it fit the current time or day. For example, if it is night-time, most skyboxes will be made to resemble night-time.

Documented Changes
There are several changes that have been documented and attributed to the Internal Clock. Note that new changes may eventually be discovered, and this page will be updated accordingly if this occurs.

Night Time
If the Internal Clock detects it is night time, several changes can occur. The most common changes is a slight change of music, as well as most skyboxes changing to be night-time. Other documented changes include the waterfall in the Castle Grounds disappearing, most walls in Princess Peach's Castle using the Third Floor texture, the dots on Toads' heads becoming stars similarly to those seen on the Toads in Star Road, and Wing Mario Over the Rainbow becoming Wing Mario Over the Starry Sky. Some people have documented The Starry-Night Skies only being available during night time, though this is unconfirmed. Interestingly, some enemies have unique behavior at night, such as the Chain Chomp in Bob-Omb Battlefield.

Day Time
Day time usually functions as the "base" of the game, with minimal changes to the game compared to the base game. The only documented changes include Big Boo's Haunt's skybox becoming day time, and The Sun becoming accessible. It is believed that day time has minimal changes due to being the most common time people will play.

Moon Phases
The Internal Clock reportedly keeps track of the phases of the moon within the game's skyboxes, changing them every 7 days to mirror real lunar cycles. On levels where the moon is visible, the phase can sometimes have minor impacts on gameplay. Documented changes include the water levels in courses such as Jolly Roger Bay and Dire, Dire Docks going up and down during New Moons and Full Moons, mirroring how moon phases alter tides in real life. Similarly, some reports mention the Chain Chomp jumping towards the sky while idle and making unique howling noises during a Full Moon, making the task of removing its stake slightly more difficult. This is likely a reference to the common misconception that wolves howl at the moon, playing off the Chain Chomp's dog-like behavior.

Halloween
If the Internal Clock detects it is Halloween, most skyboxes will be replaced with Big Boo's Haunt's skybox, songs will change to use Big Boo's Haunt's instruments, and enemies considered "scary" will appear in more levels, such as Boos appearing in Bob-omb Battlefield. Anomalous levels considered "scary" such as Big Boo's Forest also become more common. Some have reported the Ghoul Medal only being accessible during Halloween, though this has gone unconfirmed.

Christmas
If the Internal Clock detects it is Christmas, several levels will become covered in snow and use Cool, Cool Mountain and Snowman's Land's skybox and song instruments. Snow enemies such as Spindrifts and Mr. Blizzards become more common, alongside anomalous snow levels such as Chroma Tundra. The Present Boxes anomaly also is most commonly documented here.

Birthday
If the game can detect if it is the player's birthday, most commonly via asking the player when making a save file, several changes can occur. The Present Boxes anomaly can occur, though the items can be changed to be birthday-themed, as well as NPCs saying "Happy Birthday!". Notably, the anomalous Delicious Cake level has also been noted to become more common, despite minimal changes to the level being reported.

Changing Seasons
The game has been reported to have several general changes depending on what season is. Summer usually functions as the base game, though some snow levels have rarely been reported to "thaw" and experience a significant amount of Dynamic Level Rearrangement. Spring has been reported to have minimal changes, though more flowers and the anomalous Flower Fields level have been reported. During fall, the entire game is reported to have it's grass and trees turned orange, and Bob-omb Battlefield supposedly being replaced with Autumnal Battlefield. Winter has the same changes as Christmas, though it reportedly lacks the Present Boxes anomaly. All seasons appear to affect the Seasonal Sanctuary level, due to it's main mechanic being related to seasons.

Mario Day
March 10th, known as Mario Day, is considered the least common manifestation of the Internal Clock's changes. The most common documented change is the Anomalous Mario Manifestations anomaly occurring, though others have simply reported more character dialogue being directed towards Mario. Others have also reported enemies from previous Mario games, such as Rexes and the Angry Sun, manifesting, potentially meant to be referencing Mario's past where he encountered these enemies.

Easter
Easter usually has most of the changes present alongside Spring, though special things have been reported, such as MIPS being reported to be reskinned to more resemble an Easter Bunny, the Easter Eggs anomaly appearing, and supposed Bunny enemies appearing as an aggressive MIPS that would attack the player and be defeated by being thrown. Special Easter courses have been reported, though none have been confirmed.

General Changes
There are several general changes that can be applied to the game that can be found in all documented time changes. These include special missions in levels, and special NPC dialogue referring to the changes. Less drastic instances of Dynamic Level Rearrangement have also been documented to appear in all documented changes to make the levels fit the new theme.