Naruto Episode 45
Using the Transformation Technique, Naruto tricks Kiba and manages to knock Akamaru unconscious. Naruto, however, is still at a disadvantage due to Kiba’s pill-enhanced chakra and superior speed. Kiba’s onslaught ends when Naruto accidentally flatulates into Kiba’s face, stunning him due to his enhanced sense of smell. Naruto then finishes the battle with barrage of shadow clones.
Source: Wikipedia
Naruto Episode 45 – Surprise Attack! Naruto’s Secret Weapon!
