  From inherent non-linearity two gravitational waves, unless they are
unidirectional, fail to satisfy a superposition law. They collide to develop a
new spacetime carrying the imprints of the incoming waves. Same behaviour is
valid also for any massless lightlike field. As a result of the violent
collision process either a naked singularity or a Cauchy horizon (CH) develops.
It was shown by Chandrasekhar and Xanthopoulos (CX) that a particular class of
colliding gravitational waves (CGW) spacetime is locally isometric to the Kerr
metric for rotating black holes. This relation came to be known as the CX
duality. Such a duality can be exploited as an alternative derivation for the
Kerr metric as we do herein. Not each case gives rise to a CH but those which
do are transient to a black hole state provided stability requirements are met.
These classical considerations can be borrowed to shed light on black hole
formation in high energy collisions. Their questionable stability and many
other sophisticated agenda, we admit that await for a full - fledged quantum
gravity. Yet, to add an element of novelty, a quantum probe is sent in the
plane $\theta =\pi /2$ to the naked ring singularity of Kerr which develops for
the overspinning case $(a>M)$ to test it from a quantum picture. We show that
the spatial operator of the reduced Klein-Gordon equation has a unique
self-adjoint extension. As a result, the classical Kerr`s ring singularity is
healed and becomes quantum regular. Our poetic message of the paper is
summarized as
  Let there be light
  that collide with might
  to disperse the night
  and create holes that are white

General Relativity and Quantum Cosmology