  Dark matter can be boosted by various mechanisms, which may produce
characteristic signals that are different from those of canonical dark matter.
We show that the semi-annihilation $\chi\chi\to\bar{\chi}\nu$ produces signals
that are distinctive from those of other semi-annihilation and standard dark
matter annihilation processes. Because the boosted dark matter produced by the
semi-annihilation process is regarded as a high-energy neutrino, the total flux
of the dark matter and the accompanying neutrino produce double peaks in the
energy close to the dark matter mass. We show that it will be possible to
detect both of the particles produced at the Sun using future large volume
neutrino detectors such as those of the Deep Underground Neutrino Experiment
and Hyper-Kamiokande.
