Armyworms move across a field in great numbers. The symbol is read as many small pressures advancing together, each harmless alone but heavy as a mass.
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.