A poisonous fish. It is said that Telegonos, son of Ulysses by Circe, coming to Ithaca to see his father was denied admission by the servants; whereupon a quarrel ensued, and his father, coming out to see what was the matter, was accidentally struck with his son's arrow, pointed with the bone of a trygon, and died.
The lord of Ithaca. Struck by the poisonous trygon's bone, expired.
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894