A high-grade tracking-offensive ninjutsu where one calls upon ninken with a summoning, so they can tail the target from underground and assault it simultaneously with their fangs.
After the user marks an opponent with his or her blood, they roll out a scroll and smear their blood across it. Afterwards they place it between their hands and make the seals before slamming the scroll into the ground. The ninken are summoned there and travel through the ground following the scent of the blood. When the target is found, they erupt from the ground and hold down the opponent with their mouths.
In Naruto: Ultimate Ninja, Kakashi's second special move is a variation of this technique in which Bull bursts out of the ground and strikes the opponent with a double bladed sword which he holds in his mouth.
In Naruto: Ultimate Ninja Heroes, Kakashi can use a variant of this technique. Kakashi knocks the opponent unconscious and performs hand seals, finally slamming his hand on the ground. From the ground, Bull jumps out and hold the opponent firmly. Then Kakashi himself strikes the opponent several times with a kunai, before kicking the victim away.
In the English Dub, Kakashi mentioned the dogs can tear an opponent apart when Zabuza asked him if he planned to talk Zabuza to death and Kakashi replied he could do it "in a way" by giving the hounds the order. In the original, Kakashi simply told Zabuza to stop acting tough as they both knew he can't do anything while pinned down by the hounds.
This is one of the few instances in Naruto where the Dub differs from the original, a trait common in most English Dub anime adaptation, but not common in Naruto.