  Quasar-driven outflows on galactic scales are a routinely invoked ingredient
for galaxy formation models. We report the discovery of ionized gas nebulae as
traced by [O III] $\lambda$5007 AA emission surrounding three luminous red
quasars at $z \sim 0.4$ from Gemini Integral Field Unit (IFU) observations. All
these nebulae feature unprecedented pairs of "superbubbles" extending $\sim$20
kpc in diameter, and the line-of-sight velocity difference between the red- and
blue-shifted bubbles reaches up to $\sim$1200 km s$^{-1}$. Their spectacular
dual-bubble morphology (in analogy to the Galactic "Fermi bubbles") and their
kinematics provide unambiguous evidence for galaxy-wide quasar-driven outflows,
in parallel with the quasi-spherical outflows similar in size from luminous
Type-1 and -2 quasars at concordant redshift. These bubble pairs manifest
themselves as a signpost of the short-lived superbubble ``break-out'' phase,
when the quasar wind drives the bubbles to escape the confinement from the
dense environment and plunge into the galactic halo with a high-velocity
expansion.
