I got taken down by what felt like a cheesy Reaper rush in 1v1 PvT. The other player basically sacrificed everything to build a Barracks and two or three reapers (I believe he built the barracks at 7 or 8 SCVs) and got into my base shortly after my first Gate went up. I didn't build a Zealot because other things I had read recommended going straight for a Stalker (and usually this seems to work).
I scouted him, but he hid the Barracks somewhere else (probably near my base) so I didn't see it. There wasn't enough time for me to check everywhere he could have hidden it, so I'm not sure I could spot it coming.
I moved my Probes away from the Reapers, and while I did that he ran in and built a Bunker on top of my resources. At that point it was game over.
How should I counter this?
Edit for clarification
I'm redefining this as a "suicide" Reaper rush, to distinguish it from a normal Reaper rush. I was already building for a normal Reaper rush: Gate then Cybernetics, skip Zealot and go straight for a Chrono-boosted Stalker. I had just started my Cybernetics when his first Reaper showed up. I looked at his build order after and he was skipping SCVs to get a Reaper out way earlier than is normally possible. He also sent 3 SCVs to build the bunker in my base, so he was gambling everything on taking me out in that first wave.