A plumbata is a special kind of weapon that people used a long time ago. It looks like a big nail or a very pointy stick with a weight on one end. The weight is called a fustibalus, and it helps the plumbata go really far when you throw it.
When you want to use a plumbata, you hold it like a pencil and then you throw it like a baseball. When you throw it, the weight on the end makes it spin through the air. This helps the plumbata go farther and straighter, so it can hit a target that's far away.
People used plumbata as weapons because they were really good at hurting other people. When the plumbata hit someone, it would stick into their skin and hurt them a lot. So, they were used in battles and fights as a way to fight off enemies and defend themselves.
Nowadays, people don't use plumbata as weapons anymore because there are better and safer ways to protect ourselves. But, they are still very interesting historically, and people sometimes use them in games and competitions to see who can throw them the farthest or the most accurately.