  We uncover a dynamical entanglement transition in a monitored quantum system
that is heralded by a local order parameter. Classically, chaotic systems can
be stochastically controlled onto unstable periodic orbits and exhibit
controlled and uncontrolled phases as a function of the rate at which the
control is applied. We show that such control transitions persist in open
quantum systems where control is implemented with local measurements and
unitary feedback. Starting from a simple classical model with a known control
transition, we define a quantum model that exhibits a diffusive transition
between a chaotic volume-law entangled phase and a disentangled controlled
phase. Unlike other entanglement transitions in monitored quantum circuits,
this transition can also be probed by correlation functions without resolving
individual quantum trajectories.
