text: Julius Pollux recorded that this hero's dog ate some snails, thus discovering a purple dye.
full_question: Julius Pollux recorded that this hero's dog ate some snails, thus discovering a purple dye. This hero killed Syleus, who forced passersby to hoe his vineyard. This man killed Theiodamas in a dispute over a bull, and adopted a son as a companion who was later abducted by nymphs while fetching water. After Eurytus reneged on a promise to give a daughter to the winner of an archery contest, this man killed him and abducted Iole. This companion of Hylas killed Iphitus, for which he was punished by having to wear women's clothing and serve Omphale. This hero was killed by a shirt soaked in the blood of the centaur Nessus, which was given to him by his jealous wife Deianira. For 10 points, name this Greek hero who retrieved the cattle of Geryon while performing his twelve labors.
first_sentence: Julius Pollux recorded that this hero's dog ate some snails, thus discovering a purple dye.
raw_answer: Heracles [or Hercules]