A woomera, also called a spear-thrower, is a tool used by some Aboriginal people in Australia to throw a spear really far and really fast. It's kind of like a long stick with a little pocket on the end.
First, the person would put the end of the spear into the pocket on the woomera. Then, they would hold onto the woomera with one hand and pull the spear back with the other hand, kind of like pulling back on a slingshot.
Next, they would quickly swing their arm and release the spear, which would fly out of the pocket on the woomera with a lot of force. This would help the spear travel much farther and hit the target with more power.
Some Aboriginal people still use woomeras today and even decorate them with special designs that have meaning to their culture.