Horkos was the spirit of the curse that will be inflicted on any person who swears a false oath.
Horkos was born from the goddess Eris, assisted by the Erinyes (Furies), "whom Eris bore, to be a plague on those who take false oath".
One story tells of a man who took out a deposit from a friend with the intention of keeping it for himself. When the friend asked him to swear an oath regarding the deposit he recognised the danger and prepared to leave town, and while on the road he met a lame man who was also on his way out of town. When asked, the lame man said that he was Horkos (Oath), and that he was on his way to track down wicked people. The man asked Horkos how often he returned to the city, to which he replied, "I come back after forty years, or sometimes thirty." Believing himself to be free from danger, the man returned to his friend the following morning and without hesitation swore that he had never received the deposit. Within the day, Horkos had found him and dragged him to the edge of a cliff and, protesting, the man asked how the god could have said he was not coming back for thirty years when in fact he did not even grant him a day's reprieve. Horkos replied, "You also need to know that if somebody intends to provoke me, I am accustomed to come back again the very same day."