Inside Jabu-Jabu's Belly

Inside Jabu-Jabu's Belly is the third dungeon in Ocarina of Time and is set inside Lord Jabu-Jabu's body. To enter, Link must drop a fish from his bottle in front of Jabu-Jabu, causing him to open his mouth and suck both the fish and Link inside. His mission here, while he is looking for the third Spiritual Stone, Zora's Sapphire, is to rescue Princess Ruto.

Concept
While inside, Link must initially avoid the vast variety of parasitic enemies, including an especially large tentacle-like organism with electrified appendages in the shape of unstable pillars and jellyfish-like creatures called Bari, since they become much harder to kill without the Boomerang, the weapon found inside the dungeon. Shortly thereafter, Link locates Princess Ruto, inside what appears to be the stomach, who initially refuses to accept any help from Link, and accidentally falls into a hole. Once found again by the young hero, she commands him to help her recover the Sapphire. Link must carry Ruto throughout many rooms to help her find it. These rooms include areas where Link must fight numerous tentacles with the help of the boomerang, so that new areas can be explored. He then enters a large room with the Zora's Sapphire in the middle.

After taking the Zora's Sapphire, Ruto is captured, and Link is ambushed by a Big Octo that must be defeated in order to continue. After defeating it, Link continues until he eventually locates the creature causing Jabu-Jabu's discomfort: a parasite called Barinade, the dungeon's boss. Link eventually defeats Barinade, rescues Princess Ruto, and along with her, the Zora's Sapphire.

Master Quest
The dungeon has many strange changes in the Master Quest version of the game. Instead of uvula-like switches on the ceilings of Jabu Jabu's intestinal tract, now cow head switches that are attached to walls operate the opening of doors. As far as enemies go, Lizalfos and Like Likes were added to several rooms, the Parasitic Tentacles were dispersed evenly and in larger quantities throughout Jabu Jabu's insides, and invisible Keese were supplied to one room that includes an extra Gold Skulltula. Only three Tailpasarans appear in an optional room with a Gold Skulltula, and Business Scrubs were deleted from the Master Quest version. In terms of items, the Dungeon Map, Compass, and Boomerang can be obtained much earlier; the room that contained the Boomerang in the original version now contains the Compass, and vice versa. Other changes include the placement of a grown cow in a room, the addition of a water pillar in the suckhole room, and the presence of Bombchus, used to complete various new puzzles throughout the dungeon.

Minor Enemies and Traps
Shaboms Biri Octoroks Business Scrubs Stingers Bari Tailpasaran Parasitic Tentacles

Trivia

 * In the room where Link fights Big Octo, if he attempts to enter the room without Ruto, he cannot get to the Zora Sapphire on his own. He must throw Ruto into the circle to get it.
 * A similar dungeon called Jabu-Jabu's Belly can be found in Oracle of Ages.
 * In the first room after fighting the Big Octo, there is a ramp to the right. If the player changes the camera angle so that it goes through the wall for a few seconds, a Hookshot target can be seen.
 * This is the only dungeon in the game where Link is accompanied by another character (Princess Ruto) when he is warping to the dungeon's exit after defeating a boss. Interestingly, it's unknown how she arrived there, since she was taken to the second floor after taking the sacred Sapphire, and the boss's arena is in the first floor.