  The young energetic pulsar J1747-2958 ($\tau=26$ kyr, $\dot{E}=2.5\times
10^{36}$ erg s$^{-1}$) powers the Mouse pulsar wind nebula (PWN), famous for
its spectacular tail spanning 45$"$ in X-rays and 12$'$ in radio ($d\sim5$
kpc). We present the results of Chandra observations of the PWN and the
analysis of archival lower-frequency data. The Chandra HRC image reveals a
point-like source at the pulsar position, $\approx$1$'$ behind the bow shock
apex of the PWN. The flattened appearance of the compact nebula is consistent
with an equatorial outflow deformed by the ram pressure, implying that the
angle between the pulsar's spin axis and line of sight is $\sim70^\circ$ (in
agreement with the radio and $\gamma$-ray pulse profiles). The
spatially-resolved spectroscopy with Chandra ACIS shows that the power-law (PL)
spectrum steepens from $\Gamma=1.65\pm0.02$ to $3.0\pm0.1$ over the 45$'$
extent of the X-ray tail. However, the tail's X-ray spectrum integrated over
its 45$"$ length fits a single absorbed PL with $\Gamma=2.09\pm0.03$. We also
found the Mouse PWN in 150 MHz GMRT data, and a possible counterpart in 24
${\rm \mu}$m Spitzer data. The multiwavelength data suggest that, at low
frequencies, the spectrum of the X-ray-emitting tail region can be described by
a broken PL with at least one turnover between radio and X-rays. This is
consistent with synchrotron cooling of electrons injected at the termination
shock (with an SED slope of 2.2) in an equipartition magnetic field $B\sim200$
${\rm \mu G}$ and a bulk flow speed $v\sim4000$ km s$^{-1}$.
