A serpent rising from the sea is read as deep, primal emotion surfacing from the unconscious. Tradition sees in it something vast and unknown that commands respect.
When this appeared in your dream, what were you feeling?
My Cosmic Code has a private dream journal. Write a dream down and the app picks out the symbols in it, shows what dream books say about them and, over time, which words recur across your entries. The journal is stored on your device only.