  Despite not have been yet identified by the IceCube detector, events
generated from $\nu_{\tau}$ deep inelastic neutrino scattering in ice with
varied topologies, such as double cascades (often called \textit{double
bangs}), \textit{lollipops} and \textit{sugardaddies}, constitute a potential
laboratory for low-x parton studies. Here we investigate these events,
analyzing the effect of next-to-next-to-leading order (NNLO) Parton
Distribution Function (PDFs) in the total neutrino--nucleon cross section, as
compared with the color dipole formalism, where saturation effects play a major
role. Energy deposit profiles in the `bangs' are also analysed in terms of
virtual $W$-boson and tauon energy distributions and are found to be crucial in
establishing a clear signal for gluon distribution determination at very small
$x$. By taking the average (all flavor) neutrino flux ($\Phi_{\nu}\sim
E_{\nu}^{-2.3}$) into differential cross sections as a function of $\tau$ and
$W$ energies, we find significant deviations from pure DGLAP parton
interactions for neutrino energies already at a few PeV. With these findings
one aims at providing not only possible observables to be measured in large
volume neutrino detectors in the near future, but also theoretical ways of
unraveling QCD dynamics using unintegrated neutrino-nucleon cross sections in
the ultrahigh-energy frontier.
