  We present observations of population anti-inversion in the $3_1 - 4_0\ A^+$
transition of CH$_3$OH (methanol) at 107.013831 GHz toward the Galactic Center
cloud G0.253+0.016 ("The Brick"). Anti-inversion of molecular level populations
can result in absorption lines against the cosmic microwave background (CMB) in
a phenomenon known as a "dasar." We model the physical conditions under which
the 107 GHz methanol transition dases and determine that dasing occurs at
densities below $10^6$ cm$^{-3}$ and column densities between $10^{13}$ and
$10^{16}$ cm$^{-2}$. We also find that for this transition, dasing does not
strongly depend on the gas kinetic temperature. We evaluate the potential of
this tool for future deep galaxy surveys. We note that other works have already
reported absorption in this transition (e.g., in NGC 253), but we provide the
first definitive evidence that it is absorption against the CMB rather than
against undetected continuum sources.
