"A Storm-Like Battle!!" (嵐の如き戦い!!, Arashi no Gotoki Tatakai!!) is chapter 135 of the original Naruto manga.
Gamabunta attacks Gaara in his full-Shukaku transformation. Fascinated by Naruto's ability to summon Gamabunta, Gaara puts himself to sleep to bring out Shukaku's personality, giving it control of the Shukaku-likeness. Elated to have been released, Shukaku attacks, and Gamabunta has difficulty dodging. Knowing they cannot win a long-range battle, Gamabunta asks Naruto to transform him into another creature better-quipped for close combat. Naruto turns him into a fox, which attacks Shukaku. As the two giants clash, Naruto leaps from Gamabunta to attack Gaara, intending to wake him up.
In the manga, Naruto and Gamabunta transform into a regular fox, but in the anime they transform into Kurama.