  We develop a simple formalism of biased tracers that we dub $\mathit{Monkey\
bias}$. In this formalism, a biased tracer field is constructed directly in
terms of the linear matter fluctuation field and the set of derivative
operators acting on it. Such bias expansion is first organized based on the
general structure of non-linear dynamical equations for the biased tracers.
Further physical conditions, like the equivalence principle, are imposed on
tree-level correlators utilising the consistency relations. We obtain the bias
expansion up to the third-order in linear matter fluctuation in the generalized
$\Lambda$CDM background, which reproduces the previous results in the limit of
the EdS universe. This algorithmic construction of our bias operator basis is
well suited for extensions towards higher-order bias fields. Moreover, this
formalism reveals that biased tracer dynamics in generalized $\Lambda$CDM
background is not entirely degenerate with the rest of bias parameters, thus
opening a possibility of testing the background cosmology through the
observations of biased tracers.
