Fungi Forest

Fungi Forest is the fifth world of Donkey Kong 64, which is accessible after the player returns the Gloomy Galleon Boss Key to K. Lumsy's prison, and has collected 50 Golden Bananas. It is, as the name states, full of mushrooms. The stage centers around a giant Cuckoo Clock. The Cuckoo Clock has the ability to change day into night and vice-versa. Many areas are only accessible during certain times of the day. Enemies are also affected by time. They often become more hostile when the sun goes down. Dogadon is fought in a rematch by Chunky Kong here.

This world also introduces blue Kong Switches, though a blue one does appear in the lobby of Gloomy Galleon. They can only be activated once the Kongs get the Super Simian Slam potion from Cranky Kong.

Although this is the second level that Candy's Music Shop does not appear in (the first being Jungle Japes), her headphones can be found at various locations in this level.

Mill Area
This area contains several barns and mills that house several creepy enemies. Inside these mills are mechanical tasks the Kongs will have to face to get their Golden Bananas. These tasks include walking on dimly lit planks, turning on a conveyor belt, killing Bats in the attic, and battling a giant spider with Tiny Kong only. Snide's H.Q. appears in this area, but is only accessible during the day.

Giant Mushroom Area
This area has a gigantic mushroom surrounded by water. Inside the fungus, the Kongs have to climb up the different floors of this mushroom to tackle bananas and bonus barrels. These floors also lead to terraces outside, which have many other tasks as well. Cranky's Lab can be found here.

Big Tree Area
This area has a humongus redwood tree, inside of which sleeps the Owl that Diddy Kong must race (only during the night). Around the tree is a rabbit house, a smaller tree, and Lanky Kong's Kasplat.

Garden Area
This area has a tomato patch with several Tomatos surrounding an apple with a worm in it. Tiny Kong can plant seed in a hole which grows a giant living beanstalk. Funky's Store can be found here.

Enemies in Fungi Forest

 * Kasplat
 * Tomato
 * Dogadon (boss)

Day Only

 * Klump
 * Shroom
 * Zinger

Night Only

 * Bones
 * Bat
 * Kosha
 * Small Spider (during the mini-boss battle)
 * Giant Spider (mini-boss)

Trivia

 * This level was originally going to be in Rare's other Nintendo 64 game, Banjo-Kazooie (where it was called "Fungus Forest"), but was instead added to Donkey Kong 64. A picture of Fungus Forest can be seen in Banjo's house.
 * The lobby theme is based on the track known as "Advent" which has been found in Banjo-Kazooie.
 * The main theme for the level was originally composed for Banjo-Kazooie's predecessor, the cancelled SNES game Project Dream. It was titled "Temple" by the composer of both Banjo-Kazooie and Donkey Kong 64, Grant Kirkhope.
 * The boss battle against Dogadon in this level takes place in a lava arena, although the real level does not have any lava in it.
 * There is a 5-Banana Coin in this level that went undiscovered until January 28, 2017, seventeen years after the game's release. The collectible was found when Istorage, a member of the game's speedrunning community, datamined the game and found data for a 977th 5-Banana Coin located here; prior to his findings, it was assumed that there were only 976 of them in the game. The coin in question can be found in a dirt patch hidden in a patch of tall grass surrounding the DK Barrel just outside one of the mills.