What does "tower upward like a huge rock toppling," mean? " An enormous senility seemed to have settled upon him. One could have imagined him thousands of years old. I fired again into the same spot. At the second shot he did not collapse but climbed with desperate slowness to his feet and stood weakly upright, with legs sagging and head drooping. I fired a third time. That was the shot that did for him. You could see the agony of it jolt his whole body and knock the last remnant of strength from his legs. But in falling he seemed for a moment to rise, for as his hind legs collapsed beneath him he seemed to "tower upward like a huge rock toppling," his trunk reaching skyward like a tree. He trumpeted, for the first and only time. And then down he came, his belly towards me, with a crash that seemed to shake the ground even where I lay." What does "tower upward like a huge rock toppling," mean?