Not one animal but a colony working as one, the man o’ war is read as a group acting together, and as a hazard that drifts in looking harmless.
Does the traditional reading fit your dream, or did it mean something else to you?
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.