The T-X is a model of Terminator produced by Skynet in the future. One model of this unit was dispatched by Skynet into the past in order to terminate John Connor. The T-X ultimately failed in its attempts to destroy the Tech-Com resistance leader.
With the success of the mimetic polyalloy T-1000 Series, Skynet continued to develop its liquid metal technology, this time combining it with an advanced endoskeleton, similar in shape and structure to that of the Series 900. The resultant T-X Series is stronger, faster, more intelligent, and more deadly than any of Skynet's previous battle units, effectively making them redundant. However, its infiltration abilities, while impressive, are inferior to the T-800's, as they lack living tissue, the ability to sweat and bleed, thus their shape-shifting ability is only useful to a point, while a Terminator that is bleeding or possesses scars is more likely to be mistaken for an actual human.
Due to the T-X's default form being that of a young female, John Connor dubbed the T-X the "Terminatrix". 
The T-X Series has an advanced utilitarian battle chassis, weighing in excess of 150 kilos (approximately 330.6 lbs.). Protected by malleable, crystalline, ceramic armor interlaced with nano-fibers of carbon and titanium, the T-X is practically unstoppable on the battlefield, capable of sustaining vast amounts of damage with little to no effect.
Extremely strong and agile, the T-X Series is capable of moving its joints in ways that would be impossible for any human to do. Aided by artificial liquid steel lubrication, each joint has a massive degree of rotation. The neck is capable of 360-degree rotation, and the torso is capable of at least 180-degree rotation. The enhanced joints also show little to no wear or degradation when moving at high speeds, allowing the T-X Series to run at speeds in excess of 80 km per hour for brief periods of time before its power packs began to show slight decline.
The T-X Series is capable of easily crushing a human spinal column with just two fingers, and its thighs can crush with a pressure greater than an industrial hydraulic press. Its steel jaws and alloy teeth are harder than industrial diamonds, and can crush and cut through titanium, let alone human flesh and bone.
Like the earlier Series 1000, the Series T-X utilizes mimetic polyalloy. However, whereas the Series 1000 was constructed entirely from this liquid metal, the T-X series only has a liquid metal outer sheath covering its endoskeleton for infiltration purposes, which gives the T-1000 an advantage for being able to regenerate better. Like the T-1000 before it, the T-X can take the form of any human it touches, typically terminating the subject upon reproduction. The T-X seems to be able to mimic targets it sees, as well. This is seen when the T-X increases its bust size seen from a billboard, effectively confusing a L.A. patrolman. Stored within small reservoirs in the cranial casing of the T-X when in endoskeletal form, the mimetic polyalloy not only aids in infiltration, but also adds strength to the overall armor of the T-X Series.
Other than its increased strength and armor, the T-X Series is fitted with onboard weapons systems -- the first Infiltrator class to house advanced weaponry -- each located within a reconfigurable arm, underneath the mimetic polyalloy outer sheath. Within its vast internal arsenal, the T-X possesses many different weapons and tools for different missions.
Though it possesses many forms of inbuilt weapons, the primary weapon of the T-X Series is the Plasma Cannon. When deploying this weapon, the outer liquid metal skin of the T-X peels back from the right arm, and the arm reconfigures into the Plasma Cannon structure, an electric blue aura forming and intensifying around it as it charges. When fired, a tremendous burst of raw energy, 25 or 30 mm (or about an inch) in diameter is shot from the cannon. The plasma charge is strong enough to destroy a Series 1000 battle droid with a single impact.
After each shot, the weapon power cells have to recharge; the tiny plasma fusion generator in the chest cavity of the T-X taking just seconds to replace large power losses. Aside from the plasma cannon, the T-X could also form the following weapons:
- IAD ChemTech Flamethrower
- .223 Automatic Stopper
- .45 Cascader
- M41 pulse rifle (Aliens reference)
- 783 CHAIN Repeater
- ADMOR BioBlaster
- BioRail 32SR-9 (modified)
- CG45 Needler
- CONSIGLIO EBlaster
- Crescent Corridor Blaster
- EMP Generator
- Finite Rapid Cluster Gun
- HDE Predator (333b)
- HK-54334 (modified)
- KLD-Magnum Repeater
- Laser X-ray Burst Gun
- Rumsfeld P31 Caustic
- Subauro Neutralizer (.444)
- Tracking EBlaster
- TWIN Barrier Gun
- XFLRG 44mm
- M41A pulse rifle
- Nano-Disrupter (.222)
- P31 Caustic Shells x231
Another of its onboard arsenal used primarily by the T-X Series is its Nanotechnological Transjectors. By retracting the mimetic polyalloy skin from the index finger of the right hand, a 1.6 mm diameter titanium alloy drill bit can emerge from the fingertip. This is then used to drill into the casing of any electronic system, and a narrow blue aura flows through the tiny drill bit transferring a stream of nanobots (microscopically tiny robots) into the system. In a matter of milliseconds a T-X can connect with the electronic system and reprogram it, controlling it by direct link or ultra-high frequency contact via a downlink with military communications satellites under Skynet's control.
In this way, a T-X can take control of any machine (at least four at once, using its heads up display), including such things as electronic locks, automobiles or even other battle units. If it chooses to take over another battle unit, such as a T-850, the T-X can corrupt the other Terminator’s systems, leaving its CPU intact but unable to control its other functions.
The T-X Series is equipped with advanced sensor packages to aid in human identification and termination. These include infrared systems used to pick up heat signatures, and facial recognition and retina scanning systems. The T-X is also capable of analyzing DNA by sampling a small quantity of its targets blood using sensors housed within its mouth.
The T-X Series can access database computers wirelessly via phone lines by emitting a series of eleven beep tones, creating an audible connection, using its voice-processing unit. The T-X’s internal communications circuitry also allows radio signals to be broadcast on any frequency, and an onboard navigational system automatically merges with Skynet systems in the area, creating a complete map system which can be displayed on the T-X's heads up display. For safety purposes, the T-X possesses internal diagnosis circuits, and the ability to shunt delicate control circuits to protected areas if a massive voltage is incurred. 200px|right The T-X also appears to possess a limited emotional range, which it exhibits even when it is by itself (as opposed to displaying emotion to ingratiate itself with humans). This can be seen during the crane chase when it exhibits frustration and also performs a surprised double take upon realizing the T-850 is still in pursuit. And it appears to exhibit a fear response just before the T-850 finally terminates it with one of his hydrogen cores. Also, early in the film when it identifies blood as belonging to "primary target" John Connor, the T-X appears to react with an expression akin to a gasp of excitement.
The T-X is also the only machine to make feral growling noises when angered or frustrated.
- It is unknown if Series T-X is exclusively a female model, or if there were/are male equivalents (in the sense of endoskeletal structure and programming), as the mimetic sheath only grants aesthetic camouflage. It is feasible, given the advanced nature of this series, that such "male models" exist, though this has not been touched upon by either the films, or the comics.
- The X series might be designed to terminate Skynet units that have went rogue (usually as a result of reprogramming from The Resistance). In addition, John Connor dubbed the T-X model from Terminator 3: Rise of the Machines as an "Anti-Terminator Terminator".
- Another tool in its onboard weapons is a collapsible saw blade.
- Terminator 3: Eyes of the Rise
- Terminator: Infinity (Hologram simulation; in a flashback)
- Terminator: Revolution (Flashback)
- Video games