Tom Thumbs, dactyls, and Cabiri have a phallic aspect, and this is understandable enough, because they are personifications of creative forces, of which the phallus, too, is a symbol. It represents the libido, or psychic energy in its creative aspect.
Jung argues that the thumb-figure (Tom Thumb, dactyl) concentrates creative libidinal energy in diminutive form, functioning symbolically rather than semiotically as an image of generative psychic power.
, Symbols of Transformation, 1952thesis