The fifth book of the Iliad contains a curious story about the fight between Heracles and Hades at Pylos, told by Dione (395–7): τλῆ δ' Ἀΐδης ἐν τοῖσι πελώριος ὠκὺν ὀϊστόν, | εὖτέ μιν ωὐτὸς ἀνὴρ υἱὸς Διὸς αἰγιόχοιο | ἐν Πύλῳ ἐν νεκύεσσι βαλὼν ὀδύνῃσιν ἔδωκεν; the tale seems to have no clear mythological reference or at least not any known to us. Neither can one be found for the most puzzling element of this passage: the bizarre phrase in line 397 that Hades was wounded ἐν Πύλῳ ἐν νεκύεσσι, as we know nothing about a myth which might have been connected with this event. The lines in question have not been of great interest to scholars hitherto and tend to be mentioned only cursorily; even if some attempts at explanation have been made, no satisfactory solution has yet been offered. In this paper I would like to address two issues: (a) the myth(s) involved in the story and the meaning of ἐν Πύλῳ ἐν νεκύεσσι within it, and (b) the mechanisms through which the confusion of the transmitted versions of the motif of Heracles fighting various gods might have originated, amalgamating separate tales into an apparently unitary story. The motif of Heracles’ fight with Hades is particularly interesting and deserves careful examination.