Jim Crocodile Cook James " Jim " Crocodile Cook is a student hailing from South Academy who enters Duel Academy in the third year . Well - versed in earth science and Dueling , Jim serves as an ally to Jaden Yuki and the others . In the manga , Atticus Rhodes revealed Jim ' s full name as " James Crocodile Cook " ( ジェームス ・ クロコダイル ・ クック ) . In this version , James is possessed by Tragoedia and serves as an antagonist . Biography . Jim is an expert geologist and paleontologist , having taken part in an excavation of a Tyrannosaurus in the past and has a crocodile named Shirley , initially believed to be a fake by Vellian Crowler and Jean - Louis Bonaparte , who he carries around in a specially made backpack wherever he goes . Jim regards Shirley as " family " and does not consider her to be a pet . He places great trust into Shirley and often uses her as a judge of good character , which started his friendship with Jaden Yuki . Jim wields a Duel Disk in the shape of a boomerang . After saving Shirley from an animal trap , Jim injures his right eye . After regaining consciousness , he is imbued with the Eye of Orichalcum by a man who was touched by Jim ' s devotion to Shirley . The man who gave it to Jim told him it was supposed to have incredible powers when in the presence of a special comet . Afterward Jim kept his right eye bandaged . During the Duel between Jaden and Axel Brodie , Shirley began acting strangely due to electromagnetic waves coming from within the jungle . Meeting up with Jaden and his friends after Shirley inadvertently attacks Tyranno Hassleberry the next day , he and the group venture deep into the woods to investigate . Seeing another opportunity to claim Duel Energy , Thelonious Viper reactivates the signals , causing Hassleberry to act wildly and face Jim in a Survival Duel . Hassleberry quickly regains his senses and lashes out at Jim for disturbing his dinosaur monsters but is eventually defeated . After Viper ' s defeat , Jim is one of the few students that aren ' t turned into Duel Ghoul s when the academy is transported into a desert . Jim accompanies Jaden and co . to an alternate dimension and assists them in defending Duel Academy from the Duel Ghouls . After their journey into a third alternate world , Axel and Jim face Jaden , who has turned evil and begun calling himself " The Supreme King " . Jim Duels him in a desperate attempt to bring back his friend from the dark side , using his Orichalcum Eye to see into his heart , where it is revealed that he was depressed over the Duelist ' s burden that he does not have but needs , according to previous Duelists he has fought , and over the fact that he feels he needs to be evil in order to fight evil . Despite his discovery and attempts to free Jaden , Jim loses and both he and Shirley disappear , leaving the Eye of Orichalcum to fall into Axel ' s hands . Although Jim disappeared he used the Eye of Orichalcum to communicate with Axel , helping him to regain courage and to defeat The Supreme King ' s power over Jaden . He is later discovered to be alive and held prisoner with everyone else who was defeated in a Duel ( or " sent to the stars " ) , in the Duel Spirit World in an alternate dimension by Yubel and subsequently returns to his academy in episode 157 . Manga . Jim appeared in the " Yu - Gi - Oh ! GX " manga , along with the other Overseas Champions , although this time all four of them are from the American Branch of Duel Academy . Here in the manga he is referred with his full first name , " James " . Voice and mannerisms . In the Japanese version , he speaks frequently in English and gives nicknames to his companions such as " Dino Boy " and " Tomorrow Girl " for Hassleberry and Alexis , respectively . He has a habit saying " What " in English when he is surprised . In the English dub , Jim has a stereotypical Australian accent , Jaden even makes a comment about , much to Jim ' s dismay . Jim ' s name is based on Captain , the English explorer who was the first European to discover the east coast of Australia and Hawaii , the first to record circumnavigation , and mapped out Newfoundland and New Zealand . Jim is also one of the few characters who retains their original name in the dub . Jim ' s character is loosely based on the late Australian wildlife expert , as evidenced from his attitude and sense of humour . In the manga , Jim is a lot more malicious than his anime counterpart , favouring use of the Shadow Game s . Deck . Jim plays a " Fossil " Deck . His strategy relies heavily on the use of " Fossil Fusion " to remove from play the monster s in both his own and his opponent ' s Graveyard s to Summon creatures of varying strengths dependent on the Level s and Type s of the Fusion Material Monster s used for the merger . The monsters created by " Fossil Fusion " follow " reverse evolution " through the Cenozoic , Mesozoic , and Paleozoic eras ; the more ancient the monster , the more powerful it is .