He became disqualified on purpose. Killua has been influenced by his family since the moment he was born, being taught to believe that he could do nothing other than kill. If Illumi told him he wasn't worthy of a friend and shouldn't be a hunter just yet, Killua would purposely fail the exam.
While in the manga and 2011 anime adaptation Netero allows Killua to pass the exam without the need of a Second Phase via cellphone, in the 1999 anime adaptation he is present at the exam site or goes there to give the permission.
Overview. Killua returns to the game after easily passing the Hunter Exam on his second attempt. Gon, Killua, and Biscuit reunite to collect cards and beat Greed Island.
He was under a manipulation spell by Illumi, which seriously demented his thoughts. It was likely his thoughts were simplified in a way, and when he saw Bodoro as a possible threat to his friend Leorio, he went into immediate kill mode to protect his friend.
For some complicated reasons, Killua blamed himself for injuries that Gon sustained while fighting a bad guy. Killua runs away, so distraught thinking he betrayed Gon, and walking along a train track is about to be hit by a train. At the last second, Gon saves Killua with a tackle.
Chungus is credited gaming critic Jim Sterling. Sterling is said to have coined the word in 2012 as a blend of “chunky anus,” apparently used as an intentionally juvenile insult.
Despite his strange uniqueness, Chiaotzu is confirmed to be a human from Earth, just like his partner Tien. The reason for Chiaotzu's appearance is not his heritage, but the influence of Chinese fiction on Dragon Ball creator, Akira Toriyama.