The designation “serpent” is meant to remind us of the dragon’s craftiness (see Genesis 3:1). To supply a river of water in the desert is surely a cunning scheme, typically devilish (Ephesians 6:11). The serpent would provide the means the woman needs to turn her wilderness back into a Garden!
15 The serpent poured water like a river out of his mouth after the woman, to sweep her away with a flood.