009762-OO

009762-OO was the serial number for a drug outlawed by the UNSC Medical Corps in 2513. It was a mutagen designed to alter key regions in a subject's frontal lobe. The drug enhanced aggression, making the "animal" part of the mind more accessible during times of stress. Someone subjected to the mutagen has reserves of strength and endurance no normal human being could call upon. Such a person could also function under the influence of wide systemic shock that would kill a normal human. Without drugs to counter it, this mutagen would alter the subject's brain permanently, making them extremely ferocious.

This mutagen was illegally authorized and injected into the Spartan-III Gamma Company by Spartan-051 in 2551. He hoped it would increase their abilities to fight and sustain injury, making them harder to kill. This way, they would not be eradicated the way Alpha Company and Beta Company were.

To counter the agent, the drug miso-olanzapine was also administered, which is an antipsychotic, as well as cyclodexione-4, a bipolar-integration drug. Though they countered the effects of 009762-OO during periods of calm, they had to be regularly administered to the Spartan-IIIs to avoid permanent brain damage.

Deep Winter, the AI, discovered the presence of these mutagens in the Spartan's augmentations, but was shut down and replaced before he could alert anyone.