IceCube has ushered in a new era in astroparticle physics through the observation of high-energy astrophysical
neutrinos. In doing so, we have observed neutrinos with unprecedented energies and coming from the depth of the 
Universe. Observing these neutrinos not only push forward our understanding of the cosmic accelerators but also 
open up the doors to study new phenomena. Very rare processes occurring  on the long journeys of the neutrinos from their sources can be tested and energy scales beyond the reach of accelerators or high-intensity anthropogenic neutrino beams can be explored.
This talk will focus on the neutrino on the search for new phenomena with the IceCube Neutrino Telescope and the 
potential for discoveries at planned extensions of the experiment, the IceCube Upgrade and IceCube-Gen2.