Abstract: Correlation functions of operators widely separated in time in black hole backgrounds often decay semiclassically. However, for black holes with finite entropy, these correlation functions cannot decay forever. While the non-decaying behavior is erratic and depends sensitively on the microscopic details of the system, certain “averaged” behaviors of these correlation functions follow simple universal patterns, predicted by the Eigenstate Thermalization Hypothesis and random matrix level statistics. In this talk I discuss how these features can be explained in JT gravity by including effects from closed “baby” universes which can join with and split from the black hole.