Immunity bug The immunity bug is a series of bugs in " Final Fantasy VI " related to status immunity . Immunity is two - way in the game , it keeps the player from applying or taking off a status . Status immunity merely prevents the toggle of a status ; the player can ' t gain the status , but they can ' t lose it if they already have it either . This is used to make effects from relics and such permanent , except in specific cases where the game won ' t apply immunity , like Image . However , there are two instances where immunity is ignored . When a character ' s HP drops below 1 / 8 , they automatically gain Critical status no matter what . If they ' re immune to the status , they can ' t get it from Rippler and they can ' t lose it either , but they can still get it if their HP drops below 1 / 8 . List of bugs . Equipment immunity bug . If the player equips something that applies a permanent status , such as the Hermes Sandals or the Force Shield , and enter a battle with the equipped character either KO ' ed or petrified . Revive or heal them in battle , and notice that the status that their equipment or relic ( s ) should be providing doesn ' t show up . Even worse , if the player tries to apply said status , they ' ll see it have no effect on them at all . That ' s because while the game could not apply the status due to them having the KO or Petrify status , it could still apply immunity as there ' s no code that prevents immunity application . The same can be said for the Cursed Shield and the Zombie status . A returning Gau on the Veldt also demonstrates the bug ' s effects . He is not considered " alive " until he reappears up at the battle ' s supposed end , so any equipment and / or relic ( s ) he ' s wearing won ' t inflict their status either . Status immunities in this game are two - way : if a target is immune to a status but doesn ' t have it , it can ' t be given to it ; if a target is immune to a status but already has it , it can ' t be removed from it . For the game to give a permanent status ( Reflect from Reflect Ring ) , it must give both the status and immunity to it . As mentioned in the paragraph above , if a target is turned into a Zombie , it ' ll always lose certain statuses ( Blind , Poison , Critical , Berserk , Confuse , and Sleep ) , even if they were supposed to be permanent ( Cursed Shield ) . If the player tries to give the target the status again during that battle , they won ' t be able to , as it ' s still immune to the status . This can hurt the player in one very minor way associated with the Rage ; if the player is taking advantage of Gau ' s Poison absorption by giving him the Poison status before choosing a Rage that has Poison immunity , Gau will have to lose his current Rage before he can reattain the Poison status . There are three ways of executing this bug : Cursed Shield , Force Shield , and Rage . First , the shields ; when the player equips the Cursed Shield mid - battle , it causes immunity to Silence , Berserk , Confuse , and Sap . However , due to the relationship with Regen , setting Sap immunity also sets Regen immunity . This is a normal rule of the game , the same goes for Haste and Slow . The bug about to be mentioned is easy to predict ; when the player de - equips the Cursed Shield in the same battle , the immunities it sets are stripped , and only those it set . This does not account for Regen immunity , so Sap and Regen immunity will remain for the duration of the battle . For the Force Shield , just have it equipped at the beginning of the battle and leave it on the character for one turn . De - equipping the shield will give the Shell immunity and the status won ' t come off . Rage immunity bug . For Rage , the player should simply use a Rage that has immunity to or inflicts one of the following status : Sap , Regen , Slow , Haste , Stop , Shell , Protect , Reflect , and Float . Any of those immunities and given status ( if applicable ) will become permanent . For example , cast Regen on Gau , then select the Intangir Rage , hopefully he does not use Transfusion for the initial Rage attack . Because Intangir gives Vanish status , kill Gau off with a spell and then revive him . Vanish will be gone , but Regen , Haste , Shell , Protect , and Float will still be there . Try to Dispel the status effects and the player will find immunity still exists ( immunity is two - way ) . Now Gau has Regen , Haste , Shell , Protect , and Float for the rest of the battle due to implied Regen immunity and Intangir Rage giving permanent Haste , Shell , Protect , and Float . The entire bug comes from the fact that immunity to Regen , Slow , Haste , Stop , Shell , Protect , Reflect , and Float are never removed during battle as there ' s no code to do so . Other immunities that are also affected but never appear in the normal game include Dance ( technically , it does exist , but only for four monsters in the final battle ) , Rage , Freeze , Reraise , Trance , Chanting , Hidden , and Interceptor Guard . Monster immunity bug . When the Yeti powers up after using or receiving a Green Cherry , all he ' s really doing is adding all the status Miracle Shoes would give : Regen , Haste , Shell , and Protect . However , he has Sap immunity , which causes Regen immunity ( and vice versa ) , not unlike how the Haste / Slow immunities work in tandem . Because the FB command wasn ' t programmed to override status immunities , Yeti can ' t give himself Regen status due to an implied Regen immunity . This is a bug because it ' s obvious Yeti was supposed to get Regen status , but the programmer either forgot or didn ' t know what Sap immunity would do to this " attack " and made Yeti attempt the status addition anyway . Another monster that suffers from this bug is Air Force . The battle script shows that Air Force is meant to gain the Haste status after Laser Gun is defeated , however , due to the way Haste and Slow statuses work , the status will not be applied , as being immune to Slow makes the target also immune to the effects of Haste .