This illustration by Hans Sebald Beham shows Hercules slaying the centaur Nessus, who had kidnapped Hercules' wife Deianeira. Hercules used an arrow that had been dipped in the poisonous blood of the hydra. This action would come back to haunt Hercules and Deianeira; see the story of Deianeira and the cloak.
You can also find more myths and legends for the week of November 4-10 here. For more information and links to the actual javascript code, see the Myths & Legends Widget Reference Page.