I must have crossed threads like an idiot when I installed pedals for my new SPD cleats. After several miles of riding (~100-200 m), I suddenly got this inexplicable rolly, bumpy motion in my foot. The pedal looked skewed out of the crank arm. I removed it with my pedal wrench. Out came several rings of crank thread material. The pedal is fine.
The previous pedals that I removed were aluminum platforms and needed a dousing of degreaser and hot water to come unstuck.
I could probably screw the pedal back in with the remaining thread in the crank arm. Is this downright stupid to do?
EDIT: Some pictures and specs for further review
The pedal is a standard SPD Shimano road. I don't have the specific model number, I lost the box.
The crankset is an Omega FS6. It came prepackaged with my bike which was a rebuild. The former aluminum pedals were locked in there like a nightmare. The bike mechanic used thread sealant. Once I wrenched them off, I tried my best to clear out any offending sealant that remained in the threads.