Frankenduals, that is, duals composed (as in Hopi) of a nonsingular and a nonplural morpheme, display a consistent asymmetry. The first typological study of its kind shows that the element closer to the nominal is sensitive to (non)singularity, whereas the one sensitive to (non)plurality is more peripheral. This pattern impacts on morphology (dual featurally crosscuts singular and plural), morphosemantics (number features are sensitive to order of composition), and syntax and its interfaces (the features are interpreted and pronounced where they are merged). The resulting account builds on Hale's (1986) idea that features are semantically broad, ontologically flexible, and category independent.