Fafnir his foster-son Sigurd to kill the dragon. Regin instructed Sigurd to dig a pit in which he could lie in wait under the trail Fáfnir used to get to a stream and there plunge his sword, Gram, into Fafnir's heart as he crawls over the pit to the water. Regin then ran away in fear, leaving Sigurd to the task. As Sigurd dug, Odin appeared in the form of an old man with a long beard, advising the warrior to dig more trenches for the blood of Fafnir to run into, presumably so that Sigurd does not drown in the
Echidna (mythology) Echidna (mythology) In Greek mythology, Echidna (; , "She-Viper") was a monster, half-woman and half-snake, who lived alone in a cave. She was the mate of the fearsome monster Typhon and was the mother of monsters, including many of the most famous monsters of Greek myth. Echidna's family tree varies by author. The oldest genealogy relating to Echidna, Hesiod's "Theogony" (c. 8th – 7th century BC), is unclear on several points. According to Hesiod, Echidna was born to a "she" who was probably meant by Hesiod to be the sea goddess Ceto, making Echidna's likely father the sea god Phorcys;