A sub-component of dark matter with a short collision length compared to a planetary size leads to efficient accumulation of dark matter in astrophysical bodies. Such particles represent an interesting physics target since they can evade existing bounds from direct detection due to their rapid thermalization in high-density environments. In this talk, I will show that their annihilation to visible matter inside large-volume neutrino telescopes can provide a novel way to constrain or discover such particles. The signal is the most pronounced for relic masses in the GeV range, and can be efficiently constrained by existing Super-Kamiokande searches for dinucleon annihilation. I will also talk about possible neutrino signals from the annihilation of such dark matter particles, demonstrating that neutrino signals from the center of the Earth provide sensitivity to the unexplored parts of the parameter space.