Postcognition Drug

Devised by the Twelfth Division captain Mayuri Kurotsuchi, this substance supposedly grants its recipient a form of insight into the past, a faculty its creator dresses up as a predictive gift. In practice the drug is a trap rather than a boon, turning the person who takes it into an unwilling participant in a scenario Mayuri controls entirely. It sees use during the conflict against the Wandenreich.

Once it takes hold, the victim's mind is pulled into a looping replay of the fight they are in. Each time they manage to strike Mayuri down, they are rewound to a fixed earlier moment and made to face him all over again, which means the single path out of the cycle is to leave him alive. Because the drug acts on the hippocampus, the region that manages short-term recall, a victim who resets the loop more than ten times suffers a heavy backlash. The part of the brain governing balance briefly switches off, leaving them fully unable to move for thirty seconds.

Mayuri Kurotsuchi is the sole user of the compound. He extends its reach by working it into the bodily fluids of every Arrancar he has resurrected for battle, so that any foe who so much as touches those fluids is exposed to the loop as well.