"Duel Academia in Peril! The Crystal Beasts Block the Way", known as "Duel Academia in Peril! The Gem Beasts Block the Way" in the Japanese version,is the one hundred and seventy-second episode of the Yu-Gi-Oh! GX anime. It first aired in Japan on January 30, 2008.
As the KaibaCorp building in Domino City explodes around him, Jaden searches for a way out. He escapes in a gondola, but the rope snaps, though he manages to jump to a second gondola - whose rope also snaps. Jaden Summons "Elemental Hero Neos" using Yubel's powers to manifest the spirit physically. Neos saves him, and Jaden makes it back to the motorcycle that Sartorius has used, and takes it, heading for the docks to find a way back to Duel Academy. Back on the island, Trueman has taken the form of Daigo Sorano, and challenges many Duelists using his numerous clones. All accept, as they are having problems finding opponents for the Graduation Duel, due to the disappearance of those that Trueman has already defeated.
Hassleberry is still searching for Sorano in the forest, and one of the Trueman-Sorano clones appears to challenge him as well. He suggests that Hassleberry stop hanging around with Jaden, and states that in doing so, he looks down on younger students. Hassleberry replies that that's absurd - Sorano was the first friend that the made at Duel Academy, even though Sorano was in Obelisk Blue and Hassleberry in Ra Yellow. Trueman attempts to exploit the darkness in Hassleberry's heart, but is unable to, and he comments he didn't expect there to be anyone able to resist him besides Jaden. Realizing that Sorano is really Trueman, Hassleberry accepts his challenge, and both activate their Duel Disks.
Back in Domino, Jaden seems to be fatigued, and nearly drives Sartorius' motorcycle into the ocean, but he jumps off in time. Jaden meets who appears to be another clone of Trueman, but this one acts differently, even expressing concern for Jaden's current condition. Convinced that it's Trueman, Jaden begins a Duel with him. Trueman Summons multiple Crystal Beasts and Jaden realizes that he must have already defeated Jesse. Trueman responds that he will attack to wake Jaden up. During Jaden's second turn, Trueman activates "Mine Blast" which sends his final three Crystal Beasts to the Graveyard, and the activates "Rainbow Gravity" to Special Summon "Rainbow Dragon". When he attacks with it, "Polymerization" flies out of Jaden's Graveyard, and a dark aura disperses from it. Suddenly, Jaden can see clearly - he's not Dueling Trueman, he's Dueling Jesse. Having gotten Jaden's senses back to him, the Duel ends. Jaden determines that his "Polymerization" card was infected by the darkness in "Arcana Force 0 - The Fool".
Trueman again determines that there is no darkness in Hassleberry's heart for him to exploit - so he'll just have to create some. Trueman creates a vision in Hassleberry's head, and takes him back to his "past life" as a Tyranosaurus Rex. However, as such, he is a carnivore - and thus feeds on other dinosaurs, which is something that Hassleberry had never given much thought. Trueman then suggests that the dinosaur bone implanted in Hassleberry's leg is the bone of a dinosaur he ate in his past life. He then causes Hassleberry to hallucinate that he's been attacked by the dinosaurs he supposedly consumed in his past life. He then continues the Duel, and resummons "Horus the Black Flame Dragon LV8" and plays "Burial from a Different Dimension" to return three removed Dinosaur-Type monsters to Hassleberry's Graveyard, thus reducing the ATK of "Tyranno Infinity" to 1000. He attacks, wiping out the rest of Hassleberry's Life Points and absorbing him into the World of Darkness. Elsewhere, Jaden and Jesse are en route back to Duel Academy in a speedboat.
"Topaz Tiger" attacks "Burstinatrix". The effect of "Topaz Tiger" activates, increasing its ATK by 400 during the Damage Step only ("Topaz Tiger": 1600 → 2000/1000), but Jaden activates his face-down "Mirror Gate" to switch control of both battling monsters before damage is calculated. "Topaz Tiger" destroys "Burstinatrix" (Jesse 4000 → 3200). After the Damage Step, the effect of "Topaz Tiger" expires ("Topaz Tiger": 2000 → 1600/1000).
A replay occurs, but due to the last effect of "Rainbow Gravity", "Tempest" must attack "Rainbow Dragon" instead of "Cobalt Eagle". "Rainbow Dragon" then destroys "Elemental Hero Tempest" (Jaden 3400 → 2200). The force of the attack is so powerful, that it knocks "Polymerization" out of Jaden's Graveyard. This action purifies "Polymerization" of the darkness infecting it, which subsequently removes the dark spell Jaden is under. After Jaden sees that he is Dueling Jesse instead of Trueman, the Duel is called off.
Tyranno Hassleberry vs. Trueman
The Duel is shown from an unspecified point. Hassleberry has "Destroyersaurus" (1800/1100) in Attack Position and 2900 Life Points, while Trueman has "Horus the Black Flame Dragon LV8" (3000/1800) in Attack Position and "Royal Decree" on his side of the field as well as 2600 Life Points. Due to the effect of "Royal Decree", all other Trap Cards are negated.