A harpoon is a long and pointed tool that is used to catch fish or other animals that live in the water. It looks kind of like an arrow, but much bigger! A harpoon is attached to a rope or chain that is connected to a boat so that the animal can be pulled back to shore.
When a person uses a harpoon, they throw it with a lot of force into the water towards the animal they want to catch. The pointy end of the harpoon pierces the animal, and the rope or chain connecting it to the boat helps bring the animal back towards shore.
People have been using harpoons for centuries to catch fish and other sea creatures for food, and some people still use them today. But it's important to use them safely and in a way that doesn't harm the environment or the animals living in it.