Mortally wounded by Hercules, the centaur Nessus "gave the tunic he then wore to Dejanira, assuring her that from the poisoned blood which had flowed from his wounds it had received the power of calling a husband away from unlawful loves. Dejanira received it with pleasure, and this mournful present caused the death of Hercules."
Romantic Circles / Electronic Editions / The Last Man / Note: "Shirt of Nessus" from Lempriere's Classical Dictionary