Exodus 4:1-3

Then Moses said, “What if they will not believe me or listen to what I say? For they may say, ‘The LORD has not appeared to you.’ ” The LORD said to him, “What is that in your hand?” And he said, “A staff.” Then He said, “Throw it on the ground.” So he threw it on the ground, and it became a serpent; and Moses fled from it.