It was the pesky burrs in Milka's fur that led to the invention of Velcro.
George de Mestral and Milka
In 1941, George de Mestral (a Swiss engineer and inventor) and his dog Milka (an Irish pointer) went for a leisurely hike in the woods. After their walk, Milka was covered in burrs. This intrigued de Mestral, so much that he felt he could replicate the burrs' structure into something useful. After examining the burrs closely, he noticed they had microscopic hooks that allowed them to attach to his dog's fur. It was this discovery that led to his hook-and-loop fastening system. Creating the hook was not difficult, but it would take years for him to create the loop (nylon) for the hook to attach to.
He named his new invention Velcro®, a combination of the French words "velour" (velvet) and "crochet" (hook). He filed a patent in 1955, and marketed it as the "zipper-less zipper". It wasn't until the 1960s before it became a success when NASA adopted its use. Its popularity grew, and now has many uses in homes and businesses.