The myth of Arachne is not as well known as other Greek mythology. The tale is of a young woman who had impressive weaving skill. So good in fact, that she thought she was better than the gods. She challenged an old lady in a weaving contest (the old lady turned out to be Athena, the Greek Goddess, in disguise). Arachne weaved scenes of Zeus being unfaithful to his wife, and Athena was enraged. Realizing what she had done, Arachne tried to hang herself, but, having pity, Athena changed her rope to a cobweb at the last moment, and Arachne transformed into a spider beast.
Below I have created what I imagine this beast to look like hiding in her cave. Click the image for a larger version.