This harmless spider is an angulate spider, meaning it has two pronounced bumps, or horns, on its 'shoulders'. The said 'cat face' is created by these bumps (cat ears) and the rest of the abdomen. Strangely, this face is usually up-side-down as this spider prefers to sit with its head toward the ground. Usually, a large female is found hiding in plant leaves or debris off to the side of the web, awaiting a tremor in the lines of her web. Males are much smaller.
A female will lay an egg sac carrying about a hundred spider eggs in it. This egg sac will overwinter and in the spring, the spiderlings will emerge and disperse using silk lines to help carry them away, very similar to what happens in the end of Charlotte's Web.