  New evidence provided by the Gaia satellite places the location of the
runaway star J01020100-7122208 in the halo of the Milky Way (MW) rather than in
the Small Magellanic Cloud as previously thought. We conduct a reanalysis of
the star's physical and kinematic properties, which indicates that the star may
be an even more extraordinary find than previously reported. The star is a 180
Myr old 3-4 Mo G5-8 bright giant, with an effective temperature of 4800+/-100
K, a metallicity of {Fe/H]=-0.5, and a luminosity of log L/Lo=2.70+/-0.20 dex.
A comparison with evolutionary tracks identifies the star as being in a giant
or early asymptotic giant branch stage. The proper motion, combined with the
previously known radial velocity, yields a total Galactocentric space velocity
of 296 km/s. The star is currently located 6.4 kpc below the plane of the Milky
Way, but our analysis of its orbit shows it passed through the disk ~25 Myr
ago. The star's metallicity and age argue against it being native to the halo,
and we suggest that the star was likely ejected from the disk. We discuss
several ejection mechanisms, and conclude that the most likely scenario is
ejection by the Milky Way's central black hole based upon our analysis of the
star's orbit. The identification of the large radial velocity of
J01020100-7122208 came about as a happenstance of it being seen in projection
with the SMC, and we suggest that many similar objects may be revealed in Gaia
data.
