He Flies! He Jumps! He Lurks! Chief Toad Appears!

is episode 57 of the original Naruto anime.

Synopsis
While falling to his death, Naruto manages to summon Gamabunta. Angry that a child summoned him, Gamabunta starts asking where Jiraiya was. In order for Gamabunta to accept Naruto as his underling, he told Naruto that he must stay on his back the whole day without falling off.

Meanwhile in Konoha, Temari argues with Baki over breaking the treaty alliance between Konoha and Sunagakure. Later in Suna, Baki reports to the Fourth Kazekage that everything was going according to plan.

Gamabunta still tries to shake Naruto off as Jiraiya is doing "research" for his novel by spying on a group of girls. In an attempt to shake Naruto off, Gamabunta lands in a waterfall, scaring off the girls, much to Jiraiya's dismay. This then caused Naruto to fall of the toad's back, but in an effort to stay on the toad's back, he makes a chain of Shadow Clones to not let Naruto fall off.

Tired out, Naruto finally falls off the Chief Toad's back. As a reward for lasting so long, Gamabunta catches Naruto with his tongue, and claimed that no one since the Fourth Hokage had stayed on his back for so long. Knowing that Naruto is depleted of his strength, Gamabunta drops off Naruto at the Konoha Hospital.

Trivia

 * Naruto's efforts to stay atop Gamabunta are unique to the anime.