Burrs are small, prickly seed cases that cling to fur, clothing, or anything that brushes against them. They are a clever way for plants to spread their seeds over a wider area. When animals or people walk through areas with burrs, these tiny hooks attach themselves and get carried away, helping the plant grow in new locations. You might have encountered burrs while hiking in the woods or playing in a field. They can be quite annoying to remove, especially from pets or clothes. However, their unique design has inspired inventions like Velcro, which mimics how burrs stick to surfaces.