The flames attack manually after being fired.

"Dodging them once is not enough, boya!" Setsuna taunted, and Naruto shrieked when the lingering flames slithered across the ground like ebony snakes set on swallowing him.
Naruto leapt high above the flame trails, which collided on the place where he had just stood. Attaching his feet and right hand to the side of a rocky spire, he watched all the tiny flames coalesce into a gargantuan maw of living flame.
It's like it has a mind of its own!
The race began anew. Naruto raced through the vertical wall, a gigantic anaconda of black fire trailing after him. Out of a corner of his eye, he saw Setsuna following him from an adjacent mesa. The young ninja demanded his legs to outdo themselves, to reach for the top and touch the clouds.
"Hoooooooooyah!"
With a mighty leap, Naruto reached the summit, landing in the middle of an almost perfect circle no more than twenty meters in diameter. An instant later, the gathering of flames surged upwards like a tidal wave intent on swallowing him whole