The cloak is read as secrecy and concealment, the old image of moving unseen. Dream books also see it as protection, or as a mystery about yourself not yet uncovered.
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.