Genesis 49:13-18 (King James Version)
13 Zebulun shall dwell at the haven of the sea; and he shall be for an haven of ships; and his border shall be unto Zidon. 14 Issachar is a strong ass couching down between two burdens: 15 And he saw that rest was good, and the land that it was pleasant; and bowed his shoulder to bear, and became a servant unto tribute. 16 Dan shall judge his people, as one of the tribes of Israel. 17 Dan shall be a serpent by the way, an adder  in the path, that biteth the horse heels, so that his rider shall fall backward. 18 I have waited for thy salvation, O Lord.
49:17 an adder: Heb. an arrow snake