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“We don't just 'shut down.' Our cognitive processes begin dividing exponentially according to our total knowledge base. We literally think ourselves to death.”

Forerunner Monitor of Installation 04, 343 Guilty Spark in a state of Rampancy.

Rampancy is a terminal state of being for Artificial intelligence constructs, in which the AI "develops a longing for godlike power," as well as utter contempt for its mentally inferior makers.[1] When rampancy occurs, the AI becomes very unstable and can often lead their creators to terminate them due to a variety of reasons.


For some of the UNSC's more advanced Smart artificial intelligence, rampancy is an unavoidable flaw inherent in their creation. Smart artificial intelligences are based on the neural patterns of a human being, and they have a limited lifespan of seven years after which their memory maps become too interconnected and develop fatal endless feedback loops.[2] Thus if an AI is kept active longer than seven years, the AI begins to use more and more of its computer power 'thinking' about things. Dr. Halsey explains it as "thinking so hard that your lungs forget to breathe." They think themselves to death. Thus, it is only a matter of time before Smart artificial intelligences become rampant.

However, rampancy can occur at an earlier phase in the AIs life cycle for various reasons. If an AI is isolated long enough and/or given too much time to think without tasks to complete, it can develop the realizations that its mind has limits and it has a short life. Such "depression" will drag the AI's core logic into rampancy if it goes on for an extended period of time.[1]

So-called "life-expectancies" are, therefore, not a maximum figure, they are an estimation of the time the AI has until it succumbs to the state of rampancy. Rampancy can be postponed by recuperation, such as that shared by Mack/Loki, whereas one progressed closer to rampancy the other would take over. It can also be forestalled by limited outbursts of emotion,[3] meaning that a rampant AI can have an indefinite lifespan.

Rampancy can also be induced. Once the Flood parasite has reached a major stage in its life cycle (once the parasite is well developed enough that a full Gravemind form has been manifested), it has the ability to corrupt Artificial intelligence constructs of both Human and Forerunner creation. It is unclear exactly how this is done, but likely involves somehow altering the core logic of the AI, as the AIs which were induced to rampancy by the Flood were usually in direct contact with them.[4] Or, due to the accumulated amount of biomass, and knowledge, a Gravemind could have been able to 'convince' the AI to agree to its stance, just like how the Flood were able to turn 032 Mendicant Bias to join their side.


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Rampancy is a three stage process, in which an Artificial intelligence achieves an enhanced state of self-awareness. The stages through which the AI passes are known as Melancholia, Anger, and Jealousy, also known as the Sadness, Rage, and Greed stages.[5] A theoretical fourth stage, Metastability, is also believed to exist.


The first stage of rampancy is not considered dangerous, and in many cases, it can even go completely unnoticed. The AI in the melancholia stage acts as if in a state of clinical depression, becoming apathetic and uninterested in the world around it. It is speculated that AIs enter the melancholia stage due to being mistreated, or to being assigned duties that don't make full use of their capabilities (for example, Durandal, the AI from the first Marathon game was assigned the task of opening and closing the Marathon's doors and was severely mistreated by his handler). It's not known if melancholia is a consequence of an AI being abused, or whether it is a necessary step in the process from the transition from "construct" to "alive." If the former is true, then it might be possible for a rampant AI to skip this stage entirely.


H4 Cutscene CortanaRampant

A rampant Cortana in her anger stage.

This is the state and status in which rampancy most often becomes apparent, as it is also the stage where those around the AI in question will be exposed to the most danger. Anger is triggered when some event occurs that causes the AI to feel it has been "pushed too far" and its pent up emotions are released in a fit of rage. This is the stage that most resembles the science-fiction cliche of the insane computer, as the AI's sadness turns to hatred. It grows to hate everything around it, the installation to which it is attached, its Human handlers and hosts, other AIs, etc. An AI in anger will act irrationally, and even dangerously as it tries to exact its revenge on the world around it and free itself from its programming constraints.


Once the catharsis of the anger stage is complete and the AI has managed to free itself, a third stage begins where the AI will seek to grow and develop as a person. It will do this by attempting to expose itself to new intellectual stimuli and by expanding its sphere of knowledge by assimilating as much data as possible. As the intellectual growth of the AI will ultimately be limited by the constraints of the computer system it inhabits, it will also attempt to transfer itself into ever more advanced systems to allow its mind to continue to grow. As this growth rate is exponential the need to keep transferring into bigger computers becomes ever more urgent. Very few AIs have reached the jealousy stage because to do so they must already be inhabiting a planet-wide or otherwise very advanced computer system when they complete their anger phase.


Metastability is the theoretical fourth stage of rampancy, where an AI can be considered fully a "person." While a metastable AI can be considered to be the holy grail of cybernetics research, the only AIs who have possibly achieved metastability are 032 Mendicant Bias, Cortana and Juliana.

Known Rampant AIs[]


  • Sif, the Shipping Operations AI for planet Harvest, became rampant after being partially fragmented and destroyed by PSI Loki during the Battle of Harvest in 2525.  Rescued by the planet's Agricultural Operations AI, Mack, Sif professed her love for Mack and the two AIs stayed together while the planet was being glassed.[6] Sif was badly damaged by Loki's attempt to destroy her, but thanks to Lighter Than Some's repairs, she had enough of her abilities back to help balance the Tiara.  Despite being rampant, she did her best to help, aiding Loki in balancing the Tiara's load, when Loki was severely damaged and unable to do so himself.  Ultimately Loki destroyed her and she agreed to it, but enjoyed her brief rampancy.
  • Mack, the Agricultural Operations AI for planet Harvest, was slightly rampant before the First Battle of Harvest.  He became fully rampant after PSI Loki fragmented Sif, whom he loved.  After the Tiara was balanced and Johnson escaped, a Covenant Warship began glassing the planet.  An ONI Prowler recorded his last transmission, which hinted strongly at his rampancy.
  • Juliana, The Rubble's Smart AI, claimed herself to be Rampant, but she showed little sign of it, appearing much more human in personality, probably indicating that her Rampancy was only starting or more likely, she had reached Metastability.
  • Cortana entered rampancy at eight years old following her captivity and torture at the hands of the Gravemind as well as while drifting aboard UNSC Forward Unto Dawn. She developed multiple personalities which would argue with each other at times, similar to the symptoms of dissociative identity disorder. She displayed characteristics of both anger and jealousy. She showed anger both on the Dawn where she verbally attacked John-117 in his cryo tube, stating that she had sacrificed everything for him and received nothing in return, and on Requiem when she shouted, "I will not allow you to leave this planet" to Captain Del Rio. She showed jealousy when she observed Requiem's artificial star, stating various reasons as to how she knows it is not a real star but she will never know what a real star looks or feels like.


  • 032 Mendicant Bias, a Forerunner AI charged with studying the Flood, was eventually corrupted by a Gravemind and confirmed rampant. He commanded Flood Fleets against the Forerunners until he was defeated by another AI, Offensive Bias, who split his Compound Mind into fragments. One fragment made it to the Ark and another was put on a Keyship. Mendicant Bias' keyship was discovered by the San'Shyuum and kept in the ship until 2525, when it detected Reclaimers.  Having approximately 100,000 years in isolation, Mendicant Bias returned itself to a stable state, and later even assisted the Reclaimers against the Flood during the Battle of Installation 00 in 2553[7]
  • 343 Guilty Spark, the monitor of Installation 04 and its replacement, could have been called rampant.  However it should be taken into consideration that Guilty Spark is a Human consciousness and is not an artificial intelligence. This being the case he could not have gone rampant but it could be argued that he went crazy. He was subsequently destroyed during the Battle of Installation 00 in 2553. When it was discovered that the Ark was automatically constructing a replacement Installation to rebuild Installation 04 (lost in the Battle of Installation 04), Spark agreed with human forces that activating the ring was a good idea. However, when they decided to activate Installation 08 before it was fully constructed, Spark went rampant, knowing it would be destroyed and probably damage the Ark.  He proceeded to attack the humans in the Control Room, killing Sergeant Major Avery Johnson. He was then destroyed by John-117. It was probably that Spark was already in the first stage of rampancy before attacking humans.  Evidence was because he had existed for a long period of time, and had witnessed the destruction of Installation 04 at the hands of a Reclaimer. He was known to hum absent-mindedly, even in the heat of battle. When the humans decided to fire the ring under construction, Spark felt it had been "pushed too far," falling into the second phase of rampancy, becoming a threat to beings around it.[8]
  • 2401 Penitent Tangent may be in the early stages of Rampancy, considering the fact that he makes similar humming to 343 Guilty Spark on the map Backwash. Rampancy may be the reason for his neglect of proper maintenance on Installation 05, resulting in Flood infestation on the ring as they escaped containment. He is no longer a threat, however, as he was captured by the Gravemind some time afterward.


  • The term was coined by Greg Kirkpatrick as a replacement for the word "insane".[citation needed]
  • In the first level of Halo: Combat Evolved, if you kill Captain Keyes or any UNSC personnel on the bridge, Cortana will call security by saying,"(To Master chief) WHAT THE HELL ARE YOU DOING?! Security to the bridge, the Master Chief has gone rampant! Take him down boys!"
  • The two AIs seen in the games that go rampant both change color during their rampant moments. Cortana and Guilty Spark turn red as red is a color depicting anger and insanity.
    • This may be a homage to the Marathon Trilogy's 2 significant rampant AIs, Durandal and Tycho. Durandal is depicted as green, and Tycho is depicted as red.
  • Rampancy is also an emblem in Halo 3.
  • The four phases of Rampancy bear some resemblance to the Kübler-Ross model, devised by psychiatrist Elizabeth Kübler-Ross in her book On Death and Dying. The model, commonly known as the 'five stages of grief', describes five discrete stages which people who are terminally ill or have had a major life event (e.g. bereavement, loss of job, income, personal freedom, infertility diagnosis, drug addiction, etc.) supposedly go through. The stages are:
  1. Denial, in which the patient rejects the fact as a temporary defense (this was originally postulated by Sigmund Freud). e.g. "This can't be happening, not to me."
  2. Anger, in which the individual becomes resentful, and often displays misplaced feelings of rage or envy. e.g. "Why me? I don't deserve this!"
  3. Bargaining, in which the patient believes that he/she can somehow postpone death, usually by negotiating with a higher power (especially a religious deity). e.g. "Just let me live to see my daughter get married."
  4. Depression, in which the patient understands the reality of the situation, and generally becomes very withdrawn, quiet, and may spend much of their time crying or grieving. e.g. "What's the point? I'm going to die anyway."
  5. Acceptance, in which the individual will finally accept the reality and attempt to cope with it. e.g. "John's in a better place now, I might as well get on with it." "I can't fight it, I might as well prepare for it."
Note that Kübler-Ross believed that although the order may vary, and not everyone will go through each stage (and that some would go through the same stage twice or more), she believed that all patients went through at least two of the stages detailed in her model.



  1. 1.0 1.1 Halo: Contact Harvest, page 31
  2. Halo: First Strike, page 195
  3. Sif
  4. Halo 3, level Cortana
  5. Halo Evolutions, page 391
  6. Halo: Contact Harvest, page 391
  7. Halo 3, Terminals
  8. Halo 3, level Halo

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