'A worm' denotes falsity of evil in the good derived from the proprium or selfhood.

A worm 'that dies not,' as in Isaiah 66:24, denotes infernal torment related to falsity.

In Exodus 16:20, worms signify what is filthy. (Arcana Coelestia 8481)

In Deuteronomy 28:39, they signifies falsities that destroy. (Arcana Coelestia 8481)

In Isaiah 14:11, they signify the torment of internal pain. (Apocalypse Revealed 763)