And he said, Cast it on the ground. And he cast it on the ground, and it became a serpent; and Moses fled from before it. A serpent - Of what sort we know not, as the word נחש nachash is a general name for serpents, and also means several other things, see Genesis 3:1 : but it was either of a kind that he had not seen before, or one that he knew to be dangerous; for it is said, he fled from before it. Some suppose the staff was changed into a crocodile; see Clarke on Exodus 7:10 (note).
Related Commentaries of Exodus 4:3
Exodus 4:3
3 And he said, Cast it on the ground. And he cast it on the ground, and it became a serpent; and Moses fled from before it.