"I'm a Ninja!!" (忍者だ!!, Ninja da!!) is chapter 13 of the original Naruto manga.
As Kakashi holds Zabuza at knife point, Zabuza reveals that it is just another water clone. The real Zabuza appears and kicks Kakashi into a nearby lake, where he proceeds to trap Kakashi with his Water Prison Technique. Because he must remain with Kakashi to maintain the prison, Zabuza creates another water clone to deal with Tazuna and the rest of Team 7. Kakashi instructs them to flee, but Naruto, remembering his earlier vow to not run away from difficult situations, attacks the water clone.