The RX-0 Unicorn Gundam (ユニコーン ガンダム Yunikōn Gandamu?, or Unicorn, Unicorn Gundam 01, Singularity One) is the titular prototype mobile suit of the Mobile Suit Gundam Unicorn novel, its OVA adaptation and the television re-cut. Developed by Anaheim Electronics for the Earth Federation, it concealed a secret that could shake the future of all humanity, for it was the key to opening Laplace's Box. It is piloted by Banagher Links after the head of the Vist Foundation and his father, Cardeas Vist, entrusted it to him at the dawn of the Third Neo Zeon War in U.C. 0096.

Produced as the final part of the E.F.S.F's reorganization plan, the "UC Project", the Unicorn Gundam is a revolutionary design meant to be the main symbol of the project's main goal: to destroy any traces of Zeonism in the Earth Sphere. Thus, not only does it feature a Gundam design, but it also incorporates an anti-Newtype system. Two prototype machines were completed at Anaheim Electronics' factory in Granada. However, when the Vist Foundation took control of the project, they installed a special "La+ Program" OS into the Gundam, turning it into a symbol of possibility by making it the key to finding Laplace's Box: the embodied hope of the Universal Century. Featuring the most advanced mobile suit technology of the time, its performance is unmatched.

Incorporating test data from the experimental MSN-06S Sinanju Stein, the Unicorn Gundam's entire frame is built with Psycho-Frame material, drastically increasing the unit's responsiveness and allowing it to be piloted like an extension of the pilot's body. While mobile suits used during the Second Neo Zeon War implemented psycho-frame technology on a limited basis, the Unicorn is the first "full psycho-frame" mobile suit. In some cases, this responsiveness is so high that the machine appears to act on its own without any actions from the pilot. In addition, the Unicorn utilizes a special system known as the "NT-D" (or Newtype Destroyer) which activates the suit's psycho-frame and dramatically increases the suit's performance.

In its normal form, the "Unicorn Mode", the Unicorn Gundam's head is similar in appearance to those of Londo Bell's mass-produced mobile suits, with the addition of a single, horn-like antenna on its forehead (which gives it the name "Unicorn"). Destroy Mode is the form when Unicorn Gundam's NT-D System is activated. The transformation is marked by an expansion of the suit's frame. The armor seams separate and lock down into various hard-points, while the newly exposed psycho-frame emits a pinkish-red or greenish (Awakened) glow (attributed to the Psycho-Field phenomenon). In this mode, the Unicorn becomes taller, reveal six more thrusters, and its head transforms to one with standard Gundam features, the visor and face guard retracts into the head to reveal the twin eyes and mouth plate, and the antenna splitting into a V-fin. To prevent its transformation being interrupted, the strength of its I-Field will be increased temporarily. Additionally, a pair of sub-sensors are revealed on the shoulders, and two concealed beam sabers extend out of the backpack.

In Destroy Mode, the suit's psycho-frame scans the pilot's thoughts and directly transmits them to the suit's drive system; in other words, the Unicorn can be controlled by the pilot's thoughts alone. Additionally, the mode also causes the machine's performance - in thrust, generator output, and sensory radius - to be increased to unmeasurable levels. The NT-D also allows the Unicorn to take control of an enemy's psycommu weapons (also known as "Psycommu Jack") by emitting a Psycho-Field. However, the stress placed on the mind by manipulating an object more than tenfold the size of an average human is extraordinary. Even with the aid of the psycho-frame, the pilot's mind can only endure roughly five minutes of operation before a limiter is activated, deactivating the psycho-frame and returning the mobile suit to its Unicorn Mode.

With the performance limiters disengaged, the Unicorn can accelerate up to 20 G's in Destroy Mode; to alleviate such high levels of G forces placed on the pilot, a drug administration system called the "DDS" is fitted on the pilot suit. It suppresses stagnated blood circulation due to high acceleration by administering the drug to the pilot. Furthermore, the DDS activates automatically upon the detection of another Newtype via the "Intention Automatic System".