Tall, Tall Mountain

Tall, Tall Mountain is the 12th course in Super Mario 64. The course takes place on a tall mountain filled with Monty Moles and water, in which the player must scale the mountain to find various Ukikis near the top. There is also a secret slide hidden on one of the mountain walls, as well as various mushrooms to a platform on.

Missions

 * 1) SCALE THE MOUNTAIN
 * 2) MYSTERY OF THE MONKEY CAGE
 * 3) SCARY 'SHROOMS, RED COINS
 * 4) MYSTERIOUS MOUNTAINSIDE
 * 5) BREATHTAKING VIEW FROM THE BRIDGE
 * 6) BLAST TO THE LONELY MUSHROOM
 * 7) 100 COIN STAR

Mushroom Collision Oddity
The large mushroom platforms found along the edge of the course all have bent stems. However, the collision does not match their appearance, instead staying in a straight line. This suggest that earlier in development, the stems of the mushrooms were all straight. To support this, the painting for the level depicts these mushrooms with straight stems. It's likely that their stems were changed as a stylistic choice late in development, with the developers forgetting to change the collision mesh.

This oddity still exists in Super Mario 64 DS.

Super Secret Slide
In certain personalized copies of the game, players have reported that there is supposedly a second secret slide hidden in Tall, Tall Mountain. The most common way to access it is supposedly using the cannon to blast away a part of the wall on the mountain, similar to that of one of the stars in Whomp's Fortress, which will then reveal a hidden passageway to the secret slide. The slide itself is described to be very difficult, with many sharp turns, narrow passages, and even flamethrowers attempting to burn the player. Reaching the end of the slide will take the player to a room with a Star in the middle.

Varying Mountain Heights
Allegedly, in certain personalized copies of the game, the mountain's height can vary depending on how high or low the player enter's it's painting, similar to how the water level starts off in Wet-Dry World. The shortest the mountain can get is roughly half the size of it's normal counterpart, thus making certain stars such as Scale the Mountain easy to accomplish. On the other hand, the tallest the mountain can get is roughly double the size, and is said to be difficult to scale without using tactics such as Backwards Long Jumps.

Race To The Top
According to some reports of anomalies in Tall, Tall Mountain, a mission can appear known as "Race To The Top". It is usually characterized by a star appearing on top of the mountain in place of the second Ukiki. Several have claimed that this is a race with Koopa the Quick, or simply a timed star that only appears if the player reaches the top in a certain time limit, similarly to the Princess' Secret Slide.

DK Mountain
DK Mountain is a supposed early version of Tall, Tall Mountain, found replacing it's finished counterpart in some personalized copies. It is generally described nearly identically in shape to TTM, only with trees instead of mushrooms, a general vibe reminiscent of the early Donkey Kong Country games, and even an alleged boss fight against Donkey Kong, hence the name. The level was likely a homage to Donkey Kong Country, before being redesigned for some unknown reason.