Astonishing Truth! Gaara's Identity Emerges!

is episode 74 of the original Naruto anime.

Synopsis
Leaving Shino to deal with Kankurō, Sasuke continues his pursuit of Gaara. Kankurō attacks Shino with his puppet, using its many hidden weapons to catch Shino by surprise. Shino is able to dodge the attacks through the use of his destruction bugs, though eventually makes the mistake of inhaling some of the puppet's poison from a bomb. As the battle goes on, Shino directs his bugs to Kankurō's location. They consume his chakra once they get there, causing Kankurō to collapse. The battle won, Shino also collapses due to Kankurō's poison. Sasuke catches up with Gaara as Shino's battle ends, and the two resume their match. Gaara then enters his initial jinchūriki form to overwhelm Sasuke.