There was nothing in the way of fighting that Kala Nag , the old wise Black Snake , did not know , for he had stood up more than once in his time to the charge of the wounded tiger , and , curling up his soft trunk to be out of harm 's way , had knocked the springing brute sideways in mid-air with a quick sickle cut of his head , that he had invented all by himself ; had knocked him over , and kneeled upon him with his huge knees till the life went out with a gasp and a howl , and there was only a fluffy striped thing on the ground for Kala Nag to pull by the tail .