In The Old Man and the Sea, by Ernest Hemingway, Santiago is an old, experienced fisherman whose luck has changed; after eighty-four days without catching anything, today Santiago has hooked an eighteen-foot marlin and needs to kill him with his harpoon before lashing the great fish to the boat.
Your question refers to harpooning, and Santiago has his harpoon ready as the marlin circles slowly, for he knows the fish is much stronger than him. On the fish's third circle, Santiago sees his beautiful "brother" (the marlin) for the first time.
When he sees the size of the fish, Santiago is impressed but not daunted:
at the end of this circle [the fish] came to the surface only thirty yards away and the man saw his tail out of water. It was higher than a big scythe blade and a very pale lavender above the dark blue water. It raked back and as the fish swam just below the surface the old man could see his huge bulk and the purple stripes that banded him. His dorsal fin was down and his huge pectorals were spread wide.
Despite its size, Santiago treats it the same as he would any other fish, but it is a slow process. The first thing Santiago decides is that he must get the fish very close to the boat. "I mustn’t try for the head. I must get the heart. "Be calm and strong, old man,'" Santiago tells himself.
It is an arduous process. Sometimes the fish seems to play dead; Santiago tells the fish it is going to die but wonders if the fish must kill him, too? Every time the old man manages to turn the fish, the marlin swims away to circle again. Finally Santiago uses what remains of his strength to make a last effort to harpoon the fish.
He took all his pain and what was left of his strength and his long gone pride and he put it against the fish’s agony and the fish came over onto his side....
The old man dropped the line and put his foot on it and lifted the harpoon as high as he could and drove it down with all his strength, and more strength he had just summoned, into the fish’s side just behind the great chest fin that rose high in the air to the altitude of the man’s chest. He felt the iron go in and he leaned on it and drove it further and then pushed all his weight after it.
The battle is not over yet, however, as the marlin makes one final protest against dying. The giant marlin jumps out of the water, far above Santiago and his boat, crashing back into the water. Finally the fish stops moving, floating belly-up near the boat.
The shaft of the harpoon was projecting at an angle from the fish’s shoulder and the sea was discoloring with the red of the blood from his heart. First it was dark as a shoal in the blue water that was more than a mile deep. Then it spread like a cloud. The fish was silvery and still and floated with the waves.
The process of harpooning the marlin, after the rigors of catching the fish, is something Santiago knows well. This time, however, it takes all of Santiago's strength to finish his task.