I've had experience with a problem shark before, back in the 70s.
I was working as the local police chief at a small town on the island of Amity. It was just a small resort town, people from the mainland would come over for the summer to swim and lay out on the beach.
Anyways, we began having trouble with what I thought was a large shark. Some bathers had been injured. However, our mayor was not convinced. So I called upon a spunky young marine biologist from Woods Hole Oceanographic Institute. He confirmed what I thought. It was not a boating accident that had injured (fatally) the bathers, and in his words "it certainly wasn't Jack the Ripper. It was a shark."
So after a few more minor attacks, I set off with Matt Hooper (the marine biologist), and a salty old fishermen (lets just call him "Q"). We had plans to eradicate this shark. We chummed and chummed, until finally we drew him in. We I first saw the shark, I was astounded. Its head was enormous. Matt thought it was a 20 footer, Q thought it was 25 feet.
Then disaster struck. After agitating the shark by shooting it with a spear-gun several times, it breached and landed on the back of our vessel. The transom was smashed to bits. Mr. Q slid right into the jaws of the massive shark, and was unfortunately eaten alive. Hooper had disappeared earlier while scuba diving, so now I was alone. The shark swam right up to me while I was rummaging inside the stricken vessel, so I threw an aluminum 80 into its mouth. Satisfied with its new prey for the moment, the massive shark swam backwards (I didn't know they could do that) and headed out to sea.
I climbed up to the top of the Crows Nest with an extra-long bang stick and a vintage World War II rifle. Out of nowhere, the shark surfaced right below me! I jabbed it with the bang stick, but it wouldnt detonate. Tiny pock marks appeared on the sharks head, but nothing else. The monster dissappeared beneath the waves once more, then I had an idea. The aluminum 80 was still in the sharks mouth! I remember Hooper telling me that compressed air could blow up the entire boat, I'm sure that it would mess up a shark too.
Out in the distance I saw a dorsal fin rise out of the water. It was the shark. *Kapow* I fired off a shot, harmlessly passing through the water next to the shark. "Come on, blow up" I said as I squeezed the trigger again, the shark racing towards me. Another miss. *Kapow* "Blow up!" I said louder as I missed again. *Kapow* Missed again. I looked down the iron sights of that old M1 Garand, aimed as best as I could, and yelled "Smile you sono************!" *Kaboom!* The bullet struck the air tank and the shark exploded into ten thousand pieces. It was dead! Then Hooper surfaced (he had been resting on the bottom) and we swam back to shore on some old barrels.