Shirt of Nessus
From The Art and Popular Culture Encyclopedia
The Shirt of Nessus, Tunic of Nessus, Nessus-robe, or Nessus' shirt in Greek mythology was the poisoned shirt that killed Hercules. It was once a popular reference in literature. In folkloristics, it is considered an instance of the "Poison Dress" motif, Aarne-Thompson motif D1402.5.
In Greek mythology, it is the shirt (chiton) daubed with the tainted blood of the centaur Nessus that Deianeira, Hercules' wife, naïvely gave Hercules, burning him, and driving him to throw himself onto a funeral pyre.
Metaphorically, it represents "a source of misfortune from which there is no escape; a fatal present; anything that wounds the susceptibilities"