Pit (also called bottomless pit, abyss, or void) is the name given to the depths down below where the level is on top of. In games, these pits usually kill or harm creatures that fall into them, and for the most part, their bottom is unknown. In the Pikmin series, a pit's punishment on an object that falls in depends on a variety of factors.
Most areas are considered to take place at ground-level, but some areas and caves clearly take place suspended above a seemingly endless abyss. There are borders almost everywhere stopping creatures from just walking off the edge and falling down, although some enemies can take steps large enough to walk over these boundaries, and leaders can throw Pikmin or their own partners over the boundaries.
Technically, all areas contain a bottomless pit – environments that appear to be at ground-level simply keep a pit plane right under the ground. This can be proven by the fact that, in some extraordinary cases, Pikmin or leaders can go through the ground, and will act as if they had fallen into a regular pit.
The only location in Pikmin with a normal abyss is The Forest Navel, where throwing Pikmin off the stage is a possible issue.
None of the overworld areas in the game have a regular abyss, but cave sublevels with the "metal" theme take place in rusty platforms suspended by metal beams far above the pit. The following caves have such sublevels:
The only way to access abysses in Story Mode is through glitches that push objects under or off the level. In Mission Mode and Bingo Battle however, pits exist in the same fashion as in Pikmin 2, that is, as the area below metallic levels. In Mission Mode, this is Clockwork Chasm, and in Bingo Battle, this is the Rusted Labyrinth and Corroded Maze.
In general, pits are meant to kill whatever falls in, but for gameplay reasons or due to oversights, this may not always be the case.
In Pikmin, Captain Olimar is not meant to fall into the void that surrounds The Forest Navel. However, it is possible to exploit some glitches that can allow Olimar to go into the void. One of two things can happen, although it is currently not clear what causes each one to happen.
By having a Shearwig chew off the bridge connecting the main land to the island on the northwest while Olimar is on said island, the bridge will slowly be removed, revealing the walk-off ledge to the captain. Alternately, Olimar may be pushed off the stage by being compressed against a 20 pellet. As the game is not ready to handle Olimar walking off, he will not be killed but will instead continuously walk on an invisible plane. He will keep moving forward, something which cannot be controlled by the player. In some unused maps that have floors that can be walked off, the same behavior happens. Oddly, on The Forest Navel, Olimar also teleports some distance above ground level when he goes out of bounds, and when he bumps against a wall or there is terrain below him, he begins walking in a different direction at almost twice his previous speed. If in this state, he goes above other pieces of terrain, he'll simply fall on them, going back in-bounds.
Wollywogs can also be used to push Olimar into the ground and towards the void. By being compressed between the Anti-Dioxin Filter and the two nearby Wollywogs, or by being compressed against a Wollywog and the wall of the lake, Olimar will go through the floor and fall for a bit, before eventually respawning where he was. He can either appear in the same spot he started, or a bit higher above, which, in the case of the wall compression, can allow him to get on top of the wall.
In Pikmin 2, it is easier for leaders to fall into the void, although still only in unintended ways. If a leader falls off while in a regular state, he will just reappear back on top of the Research Pod or the Hocotate ship without problem. On the Awakening Wood and the Perplexing Pool, this leads to otherwise-unreachable paths.
However, if a leader falls while in a lying down state, one of two things will happen: he will either be treated as a treasure (see the other objects section below), or he will become stuck in a frozen state. What decides the outcome seems to be purely random.
In Pikmin 3, falling into the abyss was hard, but possible, prior to the 1.4.0 update. Before said version, leaders could only touch the pit plane by glitching into walls. Much like in Pikmin 2, leaders that touch the void are merely respawned back in a specific location, which can be used to skip portions of the area. After the aforementioned update, leaders started taking damage when falling off (one third of their maximum health), and would respawn back on the stage, although in a different place than before, removing some exploits. In Pikmin 3, with the existence of the Rusted Labyrinth, it is possible for leaders to be thrown into the abyss, making it the first time in the series in which leaders can touch the abyss on purpose, instead of only with exploits.
Pikmin that fall into the abyss will be killed. In Pikmin 3, their death scream is long and high-pitched, clearly noting that they have been thrown into one. Although rare, it is possible for Pikmin to touch the pit plane on seemingly "pitless" areas, via a glitch such as the crushing glitch.
In Pikmin, bomb-rock Yellow Pikmin that touch the pit will cause the bomb-rock to explode instantly, but with some peculiar behavior – the explosion happens roughly on the right spot, but at ground level, and is invisible and silent. This explosion can harm leaders and Pikmin.. An easy way to see this in action is by going to the corridors with fire geysers on The Forest Navel, having a group of Pikmin, and throwing a bomb-rock Pikmin down into the pit, as close to the ledge as possible. There's a chance that an invisible explosion will kill the Pikmin on the corridor.
In the first two games, enemies that fall in a pit are killed right away. If the enemy was carrying a treasure, said treasure will just reappear on the stage.
In Pikmin, the only way to see enemies fall off is by luring a Shearwig into an area with a low boundary, damaging it, and hoping it flies over it. Other than that, there is a presumed glitch with the Beady Long Legs, in that if it escapes its arena, and is lured to the bottomless pit near the section with the Libra, the game will freeze.
In Pikmin 2, the boundaries on some of the metal-themed cave sublevels are low enough for large enemies to cross over, such as Gatling Groinks and Fiery Bulblaxes. These enemies can be made to cross the edge by having prey on the other side; they'll walk off while attempting to chase their target. This can be exploited in order to kill the enemies easily and without consequence. Enemy corpses are treated as treasures (see the other objects section below)
For Pikmin 3, the rules were changed a bit: enemies that fall off the edge are put back onto the ledge that they fell off of in a similar way to that of the leaders. The enemies, however, do not take any damage. This is observable in Mission Mode in stages such as the Clockwork Chasm, and in Bingo Battle in stages such as the Corroded Maze.
In Pikmin 2, treasures that fall off will simply reappear back on the stage near the point they fell. Specifically, they reappear on the closest carrying waypoint. This is also true for treasures being carried by Dweevils or treasures that are inside undefeated enemies.
In Pikmin, if the cursor is placed on a bottomless pit, it sinks to the bottom and becomes invisible. In Pikmin 2, New Play Control! Pikmin, New Play Control! Pikmin 2, and Pikmin 3 (all control schemes), it stays on an invisible plane at ground level.
In Pikmin 3, fruits, treasures, and minor objects that fall into the abyss will simply reappear at their original location.