  The unusual multiwavelength lightcurves of GRB 101225A are revisited by
assuming that it is from an off-axis GRB powered by a newborn magnetar. We show
that its optical afterglow lightcurve is fitted with the forward shock model by
parameterizing its jet structure as a Gaussian function with a half opening
angle of the jet core as $1.67^{\rm o}$. The derived initial Lorentz factor
($\Gamma_0$) is 120, and the viewing angle to the jet axis is
$\theta_v=3.7^{\rm o}$. Tentative QPO signatures of $P=488$ seconds and
$P=250\sim 300$ seconds are found with a confidence level of 90\% by analysing
its X-ray flares observed in the time interval of $[4900,\ 7500]$ seconds. Its
global gamma-ray/X-ray lightcurve and the QPO signatures are represented with
the magnetar dipole radiation (DR) model by considering the magnetar precession
motion, assuming that the magnetar spindown is dominated by the GW emission.
The bulk Lorentz factor of the DR ejecta is limited to 8, being much lower than
$\Gamma_0$. Comparing GRB 101225A with the extremely off-axis GRB 170817A, we
suspect that the nature of the two-component jet in GRB 170817A is a
combination of a co-axial GRB jet and a DR ejecta. GRB 101225A would be among
the brightest ones of the CDF-S XT2 like X-ray transient population driven by
newborn magnetars. Discussion on detectability of its gravitational wave
emission is also presented.
