Geosgaeno Geosgaeno is a geo - type fiend in " Final Fantasy X " that appears on the Baaj ruins to threaten Tidus when he tries to find shelter in a derelict temple near the beginning of the game . After three turns , Tidus wisely decides to flee . Later on , once the party has gained control of the " Fahrenheit " , the ruins can be revisited , and Tidus , now accompanied by Wakka and Rikku , can attempt to defeat the boss and enter the Chamber of the Fayth which houses the fayth of the hidden aeon Anima . Geosgaeno can drop weapons with No Encounters , and armor with Auto - Reflect . Since No Encounters cannot be customized to a weapon , only on armor , defeating Geosgaeno is the only way to obtain a weapon with this ability with a 50 % possibility of it dropping one . Battle . First encounter . When encountered in the beginning of the game , Geosgaeno ' s every attack halves Tidus ' s current HP . After three turns the battle will end with a cutscene . If the monster is killed ( only possible through use of a cheating device , such as GameShark , to alter Tidus ' s stats ) , the cutscene will play as if the battle had ended normally . One should not waste turns and Potions healing , as every attack simply halves Tidus ' s HP . Second battle . In the later battle , Geosgaeno attacks with Stone Punch , which may cause Petrify . Because the fight takes place underwater , petrified party members will instantly shatter , making them inoperable . Geosgaeno uses KO Punch to always inflict Curse and it may instantly kill a character . Geosgaeno has 95 % resistance to Poison . Geosgaeno occasionally inhales a party member . When this happens , all positive status effect s , such as Protect or Haste , will be transferred to Geosgaeno so long as the character is contained within it . The inhaled character may Struggle with a Trigger Command or defend . If the inhaled does not Struggle , on its next turn Geosgaeno will exhale the character , leaving them with one HP and dealing the inhaled ' s current HP minus 1 damage to each party member . If they do Struggle , Geosgaeno will exhale and only KO the one who was swallowed . If a character is swallowed and Geosgaeno is defeated , it will deal 9 , 999 points of damage to all party members . Strategy . It is advised to have armor with Stone Ward or Stoneproof , as well as Death Ward or Deathproof . Auto - Phoenix and Auto - Haste ensure Geosgaeno gets only a few turns . One should never defeat Geosgaeno if a party member is swallowed . A simple strategy is equipping a weapon with any elemental affinity ( e . g . Firestrike ) onto Tidus and use Quick Hit or , if possible , customize a empty four slot Variable Steel with all four elemental strikes to change into Crystal Sword for Tidus for maximum damage , but it will cost 100 , 000 gil . Hastega is a good option if the party doesn ' t have Auto - Haste . Rikku can use elemental crystals and Wakka can use his Overdrive Element Reels . The best strategy is to use Mix and combine two Gambler ' s Spirits and use Trio of 9999 to end the fight within seconds . An easy way to get Gambler ' s Spirits early is to unlock the Earth Eater by capturing all of the Calm Lands and Cavern of the Stolen Fayth fiends . Challenging the Earth Eater will be free the first time , but every subsequent battle will cost 15 , 000 gil . One will not be able to beat the Earth Eater at this point , but one can use Haste and steal the Gambler ' s Spirits . Alternatively if Spare Change was picked up on Rikku and the player has the extra cash , Geosgaeno can be killed on one turn by tossing 10 times its health at it . Given it has 32 , 767 health that would be 327 , 670 gil . The cost can be reduced if the party has charged Overdrives they use before using Spare Change to lower its health . Using a Sensor weapon , the player can see how much health it has and throw 10 times that amount to kill it . Another possible strategy is to equip either Tidus , Wakka or Rikku with the Evade & Counter armor . When a party member gets sucked in they must not struggle but defend by pressing . The character with Evade & Counter may also use Guard or Sentinel to nullify Geosgaeno ' s punch attacks . Other appearances . " Triple Triad " . Geosgaeno appears on a Triple Triad card in the version available via " Final Fantasy Portal App " .