Lalotai

"Don't worry, it's a lot farther down than it looks."

- Maui Lalotai is a realm inhabited by monsters that appears in the Disney 2016 film Moana.

Background
Also known as the Realm of Monsters, the entrance to Lalotai can be accessed atop a high mountain on a remote island. The passageway (a pit) leads to an undersea environment homed to a number of exotic, demonic and ferocious creatures — one of which being Tamatoa, a villainous giant crab.

To unlock Lalotai's entrance, one must perform the haka followed by a forceful ground smash. The necessary impact of the smash implies that Lalotai's entrance can only be accessed by beings with supernatural strength.

One can exit Lalotai by simply swimming to the surface, or by being blowed up by geyser - like jets of water. This will directly take you to the human world. Even monsters may be launched to the surface by water jets.

Monsters

 * Carnivorous Plants - Monstrous plants that are the first monsters appearing in Lalotai. They appear to be diamond-shaped plants on roots that have glowing red eyes, fangs, and a very long tongue. Moana Waialiki was almost eaten by one of them, but it's tongue was bitten off by another carnivorous plant.
 * 8-Eyed Bats - Hostile bats with 8 eyes that repeatedly tried to attack Moana. Maui is seen defeating one of them in "You're Welcome".
 * Red scaled Monster - A scaled, red monster which was briefly seen in "You're Welcome". It can be differentiated from the eel as it has scales, its facial impression somewhat resembling more of reptiles or dragons/sea-serpents, lacking fins, and its tongue is forked like that of snakes.
 * Spiked Monster - A gargantuan being with projections of various sizes on its backs and head. Its size and weight is overwhelming; it causes rumbling of the ground by walking.
 * Masked Monster -  Being rather ominous and unpredictable, it has humanoid body with four, long arms with sharp claws. The most notable feature of this creature is its face strongly resembles Polynesian tribal masks portraying two different facial structures upside down, one resembling Flash from Zootopia. It seemingly can rotate its head/neck. Was ejected by the geyser.
 * Other Monsters -  A giant octopus and a giant hummingbird were portrayed on Maui's tatoo as some of his past accomplishments.
 * Tamatoa

Places of Interest

 * Tamatoa's Lair: The home of Tamatoa

Trivia

 * Lalotai is a proto-Polynesian term that means "under the ocean".
 * Lalotai is also known as "the underworld".
 * Originally, Lalotai was to be a realm inhabited by ancestral spirits, as opposed to monsters.
 * The creatures found in Lalotai were inspired by real deep sea fish, as well as creatures from Maui's legends, such as the great eel.
 * Some of the monsters in Lalotai made cameo appearances earlier in the movie during "You're Welcome".
 * Maui had a grandmother named Hina who served as the guardian of Lalotai's entrance in earlier drafts the movie.
 * Some speculate that the spiked monster is an interpretation of Marshmallow from the Frozen.