  We present the detection and analysis of a weak low-ionization absorber at $z
= 0.12122$ along the blazar sightline PG~$1424+240$, using spectroscopic data
from both $HST$/COS and STIS. The absorber is a weak Mg II analogue, with
incidence of weak C II and Si II, along with multi-component C IV and O VI. The
low ions are tracing a dense ($n_{H} \sim 10^{-3}$ cm$^{-3}$) parsec scale
cloud of solar or higher metallicity. The kinematically coincident higher ions
are either from a more diffuse ($n_{H} \sim 10^{-5} - 10^{-4}$ cm$^{-3}$)
photoionized phase of kiloparsec scale dimensions, or are tracing a warm (T
$\sim 2 \times 10^{5}$ K) collisionally ionized transition temperature plasma
layer. The absorber resides in a galaxy overdense region, with 18 luminous ($>
L^*$) galaxies within a projected radius of $5$ Mpc and $750$ km s$^{-1}$ of
the absorber. The multi-phase properties, high metallicity and proximity to a
$1.4$ $L^*$ galaxy, at $\rho \sim 200$ kpc and $|\Delta v| = 11$ km s$^{-1}$
separation, favors the possibility of the absorption tracing circumgalactic
gas. The absorber serves as an example of weak Mg II - O VI systems as a means
to study multiphase high velocity clouds in external galaxies.
