The Rapiddo Sukina is one of the bloodiest attacks used by Tosas. It is performed when the defensive dog rips the flesh of the offensive dog until it's body can barely be seen because of all the blood. If the offensive dog gets away while the attack is being performed, it'll eventually die from it's injuries. If the attack is performed quickly enough, it can make the blood splash on the defensive dog.
This attack is also used by most of the wolves in the story and Oscar learns it when Takeru tries to use it on him.
Dogs that use this attack:
Ookami