Bohrok

The Bohrok were a swarm of mechanical insectoids controlled by the parasitic Krana located in their heads.

Description
The Bohrok are completely mechanical creatures, unlike most other beings in the BIONICLE Universe. They are controlled by the Krana located behind their headplates and share a hive mind. The Krana in turn are commanded by the Bohrok queens, the Bahrag. If a Bohrok were to lose its Krana, it would cease functions. However, Bohrok also have the ability to launch Krana at opponents, which can steal the mind of any who wear it. The Bohrok are granted abilities by the Krana, the type of power being determined by which type of Krana, similar to that of Kanohi masks.

The Bohrok have the ability to quickly extend their necks and to perform a headbutt. They can also roll up into a ball to move quickly. They also have shields in their hands through which they channel their elemental powers. These are determined by the breed of the Bohrok. Finally, Bohrok have the ability to form two different Kaita, but have never been seen doing so.

The Bohrok had a nest structure that centralized below the continent of Mata Nui. However, the nests extend quite a ways, partially extending below Metru Nui and perhaps other continents. The first Bohrok were created by the Great Beings. Later Bohrok are created when Av-Matoran reach the end of their lifespans. They are awoken by a specific sonic pitch.

Mission
The mission of the Bohrok swarms was "to clean". To do this, they would destroy anything in sight. They did everything from destroying trees to collapsing tunnels. What this was to accomplish wasn't initially clear. It was discovered far later that clearing the continent of Mata Nui, which was actually the face of the Mata Nui robot, helped allow the robot to rise.

Main six breeds
The main six types of Bohrok and their respective elements are as follows:
 * Tahnok - Fire
 * Gahlok - Water
 * Lehvak - Acid
 * Pahrak - Stone
 * Nuhvok - Earth
 * Kohrok - Ice

Bohrok Va
Bohrok Va were smaller, secondary Bohrok that assisted the main forces. They served duties such as scouting, exchanging of Krana, and other work. They aren't nearly as physically strong as the main Bohrok.

Bohrok-Kal
The Bohrok-Kal were six elite mutated Bohrok that awaken upon the defeat of the Bahrag. Their mission was to free the Bahrag from their prison. They had far greater powers than that of their counterparts and had the ability to speak. They were defeated by overloading them with the power of the Nuva Symbols.

Fohrok
The Fohrok as they have been nicknamed are fake Bohrok created by the Brotherhood of Makuta to serve in its forces. They are not controlled by Krana and were created upon studying of a swarm of Bohrok defeated by the Toa Hagah. They are blue and yellow in color.

Appearances

 * Mata Nui Online Game
 * BIONICLE Comic Series
 * BIONICLE Chronicles 2: Beware the Bohrok
 * BIONICLE Chronicles 3: Makuta's Revenge
 * BIONICLE: Mask of Light
 * BIONICLE Legends 7: Prisoners of the Pit
 * Bionicle Heroes (non-canonical)
 * BIONICLE Legends 10: Swamp of Secrets