  When subhalos infall into galaxy clusters, their gas content is ram pressure
stripped by the intracluster medium (ICM) and may turn into cometary tails. We
report the discovery of two spectacular X-ray double tails in a single galaxy
cluster, Z8338, revealed by 70 ks Chandra observations. The brighter one, with
an X-ray bolometric luminosity of $3.9 \times 10^{42}{\rm\ erg\ s}^{-1}$, is a
detached tail stripped from the host halo and extended at least 250 kpc in
projection. The head of the detached tail is a cool core with the front tip of
the cold front $\sim$ 30 kpc away from the nucleus of its former host galaxy.
The cooling time of the detached cool core is $\sim 0.3$ Gyr. For the detached
gas, the gravity of the once-associated dark matter halo further enhances the
Rayleigh-Taylor (RT) instability. From its survival, we find that a magnetic
field of a few $\mu$G is required to suppress the hydrodynamic instability. The
X-ray temperature in the tail increases from 0.9 keV at the front tip to 1.6
keV in the wake region, which suggests the turbulent mixing with the hotter
ICM. The fainter double X-ray tail, with a total X-ray luminosity of $2.7
\times 10^{42}{\rm\ erg\ s}^{-1}$, appears to stem from the cool core of a
subcluster in Z8338, and likely was formed during the ongoing merger. This
example suggests that X-ray cool cores can be displaced and eventually
destroyed by mergers, while the displaced cool cores can survive for some
extended period of time.
