Despite enormous experimental investment in searches of particle darkmatter, certain well-motivated corners of parameter space remain to beelusive "blind spots" for direct detection. In my talk I will address two ofsuch exceptions: light particles that simply do not have enough kineticenergy to detect, and strongly-interacting particles that quickly thermalizeand also become sub-threshold for direct detection. I show that both blindspots can be probed through double collisions of Dark matter -- first withsome energetic Standard model particles (solar electrons, cosmic rays,particles in a beam, neutrons in nuclear reactors etc) that bring DM toenergies above thresholds followed by the scattering inside a detector. Thisway, I derive novel constraints on light dark matter, as well as stronglyinteractingdark matter models, using existing dark matter and neutrinoexperiments.
