Are We Looking at Neutrino Absorption Spectra at IceCube?

The observed spectrum of ultrahigh energy neutrinos at IceCube might be indicative of absorption of such neutrinos in ultralight dark matter halos. We point out that various features of this spectrum can be explained by such absorptions. For a light $Z^{\mathrm{\prime }}$-mediated $t$-channel interaction between dark matter and neutrinos, we propose a novel mechanism of absorption of these neutrinos at particular energies. This can save the models of AGN predicting large neutrino flux at energies more than a PeV.