<p>Cold-forming processing is a crucial means for the cost-effective production of metal and alloy products. However, this process often results in catastrophic fracture when applied to most inorganic semiconductors owing to their inherent brittleness. Here we report the unique room-temperature plastic deformation mechanism involving sublattice amorphization coupled with Ag-ion diffusion in inorganic semiconductors Ag₂Te_1–<i>x</i>S_<i>x</i> (0.3 ≤ <i>x</i> ≤ 0.6), and an ultrahigh extensibility of up to 10,150%. Once subject to external stress, the crystalline Te/S sublattice undergoes a uniform transformation into an amorphous state, whereas the Ag cations continuously bond with Te/S anions, endowing bulk Ag₂Te_1–<i>x</i>S_<i>x</i> with exceptional plastic deformability. Remarkably, even slight polishing can induce sublattice amorphization in the surface layers. Furthermore, this sublattice amorphization can be reversed to crystals through simple annealing, enlightening the iterative sublattice amorphization strategy, with which metal-like wire drawing, curving, forging and ultrahigh ductility have been obtained in bulk Ag₂Te_1–<i>x</i>S_<i>x</i> at room temperature. These results highlight sublattice amorphization as a critical plastic deformation mechanism in silver chalcogenide inorganic semiconductors, which will facilitate their applications in flexible electronics and drive further exploration of more plastic inorganic semiconductors.</p>