  Motivated by the famous ink-drop experiment, where ink droplets are used to
determine the chaoticity of a fluid, we propose an experimentally implementable
method for measuring the scrambling capacity of quantum processes. Here, a
system of interest interacts with a small quantum probe whose dynamical
properties identify the chaoticity of the system. Specifically, we propose a
fully quantum version of the out-of-time-order correlator (OTOC) - which we
term the out-of-time-order matrix (OTOM) - whose correlations offer clear
information theoretic meanings about the chaoticity of a process. We illustrate
the utility of the OTOM as a signature of chaos using random unitary processes
as well as in the quantum kicked rotor, where the chaoticity is tuneable.
