  In this paper, we investigate a critical behavior of JT gravity, a model of
two-dimensional quantum gravity on constant negatively curved spacetimes. Our
approach involves using techniques from random maps to investigate the
generating function of Weil--Petersson volumes, which count random hyperbolic
surfaces with defects. The defects are weighted geodesic boundaries, and
criticality is reached by tuning the weights to the regime where macroscopic
holes emerge in the hyperbolic surface, namely \textit{non-generic
criticality}. We analyze the impact of this critical regime on some universal
features, such as its density of states. We present a family of models that
interpolates between systems with $\rho_0(E)\sim\sqrt{E-E_0}$ and
$\rho_0(E)\sim (E-E_0)^{3/2}$, which are commonly found in models of JT gravity
coupled to dynamical end-of-the-world and FZZT branes, and give a precise
definition of what this phase transition means from the random geometry point
of view.
