Accuracy underflow bug

The Accuracy Underflow Bug is a glitch in some versions of Final Fantasy XII. When a low level character with extremely low Magic attempts to use a status move on a target with very high Vitality and the accuracy of the spell becomes less than zero, the accuracy will underflow to 100%, allowing certain status spells to always succeed.

This bug can be useful to trivialize many late-game boss fights by continuously exploiting their status vulnerabilities, such as infinitely confusing Daedalus, Tyrant and Pandaemonium, immobilizing Shemhazai, or putting Fenrir to sleep.

The glitch works in the Japanese and North American versions, but is patched in PAL regions.