This work formalizes the concept of the Metachronon as a nonlinear temporal phase transition occurring in both human cognition and advanced artificial agents. Derived from the XChronos project, the Metachronon is defined as a discontinuous reorganization of internal models, policies, and interpretative structures. The article applies this framework to recent developments in Google's Sema 2 self-improving agent and Genie 3 world model, establishing the Metachronon as a cross-domain analytical tool connecting phenomenology, systems theory, and machine learning.