Brief oscillatory sparks control the feed composition of multicomponent vapors, which are mixed and quenched to directly transform into alloys of distinct families, some of which are unprecedented. This vapor-crystal transformation enables virtually unlimited mixing possibilities for manufacturing alloys with nanosizestabilized mixing. This fundamental understanding provides new practical capabilities in additive manufacturing and catalysis. The results presented here thus expand the landscape of high-entropy alloys, catalysts, and nanoscale additive manufacturing.