On my initial descent from my neighborhood, I felt something strange beneath my right foot, where I'd normally be securely clipped into an SPD/SL road pedal. I felt it again and then my foot came away from the crank.

Yup. The bearing seized and the spindle threads backed out from the crank arm. What the heck? The pedal was still clipped to my right foot. It was dark but not too cold, so I sat down to inspect things. With a frozen spindle, there was no way to ride the bike except one-footed.

I walked it home, swapped out a right pedal from another road bike, and continued on my ride to work. I wonder if I can salvage the failed pedal? I'll find out tonight.

Nice day, though, as it'll be in the 60s for today's commute home. Yay!