  In the eternal AdS black hole geometry, we consider two signals sent from the
boundaries into the black hole interior shared between the two asymptotic
regions. We compute three different out-of-time-order six-point functions to
quantify various properties of the collision of these signals behind the
horizons: (i) We diagnose the strength of the collision by probing the
two-signal state on a late time slice with boundary operators. (ii) We quantify
two-sided operator growth, which provides a dual description of the signals
meeting in the black hole interior, in terms of the quantum butterfly effect
and quantum circuits. (iii) We consider an explicit coupling between the left
and right CFTs to make the wormhole traversable and extract information about
the collision product from behind the horizon. At a technical level, our
results rely on the method of eikonal resummation to obtain the relevant
gravitational contributions to Lorentzian six-point functions at all orders in
the $G_N$-expansion. We observe that such correlation functions display an
intriguing factorization property. We corroborate these results with geodesic
computations of six-point functions in two- and three-dimensional gravity.
