Overseer

Overseers are thin, hologram-like beings that pop out of the ground rapidly and appear to be watching Slugcat. One in particular has taken an interest in guiding Slugcat to serve some goal...

Yellow Overseer
The yellow Overseer you meet at the beginning of the game (known by some as "Iggy") acts as a basic tutorial and as a guide.

Signs
As well as teaching the player the controls, the yellow guide will point to things and generate a yellow symbol with an arrow pointing at the subject. The symbols are:
 * Fourth+Second Karma Symbol: This symbol means "this wants to eat you" when the yellow guide points to something. This symbol will flash between yellow and red, indicating that it's dangerous.


 * Batfly Outline: points towards colonies of Batflies
 * Shelter Symbol: points towards the direction of the nearest shelter.
 * Level 4 Karma Symbol: points towards the location of edible plants. Sometimes alternates between spear symbol, indicating a popcorn plant.


 * Hologram: Occasionally you will be shown images inside yellow octagons, clumsy attempts to communicate important messages about what you are expected to do.
 * Slugcat Head: points towards a route out of the current region, attempting to lead you in some new direction.
 * Alternate Head: points towards a route to its destination, Looks to the Moon.
 * Neuron Symbol: Points a path upwards, towards a new destination.

Blue Overseers
Blue Overseers appear randomly and will observe the player. These creatures can be found alone, or in groups of two or three. Blue Overseers can be seen interacting with each other, connecting their tendrils together to generate little sparks. These can be killed and will drop an Overseer eye, which can be brought to Big Sister Moon for some information about the overseers. These overseers apparently belong to Five Pebbles.

Green Overseer
On very rare occasions, a green overseer will spawn instead of a blue one. The change is purely cosmetic, but it is implied that the overseer belongs to a more faraway being that sent the Hunter on their quest. The green overseer can only be found in subterranean with a 1% spawn chance.

Trivia

 * When a Scavenger spots an Overseer, it will attempt to spear it and kill it. Moon states, when given an Overseer carcass, they do this as an act of defiance.
 * The symbols the yellow Overseer flashes are related to the karma symbols seen upon hibernation. It flashes the fourth karma symbol in reference to edible objects, and this has been deciphered (using other in-game evidence) to be a symbol representing gluttony. The first karma symbol, likely wrath, is used in conjunction with the fourth gluttony symbol when the Overseer points at a threat, meaning "This thing will kill/eat you".
 * It is heavily implied that Iterators have the same color pearls as they do Overseers.
 * If Slugcat eats Moon's neurons, the yellow Overssers will appear shortly afterward, expressing their disapproval by shining red Xes and pictures of Slugcat's corpse on him.
 * The yellow Overseer can light up dark areas within the Shaded Citadel for the Slugcat when playing as the Monk in order to aid it in its traversal.OverseerIllumination1.jpg

Arena
There are four unique overseers in the arena sandbox mode, a white, a yellow, a red and a black overseer, and they are used to place objects in the map. Each of the overseers' colors indicate their slugcat's color, the white one teams with the survivor, the yellow one teams with the monk, the red one teams with the hunter and the black one teams with the unnamed black slugcat.

Once all items & creatures are in their places and the edit mode is exited from, the colorful overseers will disappear and the slugcats will consequently appear. Just like the black slugcat, the colorful overseers don't appear in single-player mode and are most likely not canon. In addition, the yellow overseer in the arena mode has a stronger color than the one we see in single-player mode, which might indicate that the two are not the same overseer.