Ankle "locked up" - what happened here?

Yesterday I was at a yoga class with my bestie and after class we were messing around trying to contort into a weird lift. I was flexing my foot in a peculiar way trying to shift into this lift and I felt a weird twinge. At this point my ankle and foot became locked in this flexed position, turned inward, and I could not unflex or move my foot. Friend asked me to wiggle my toes, and I could not do that either. It did not hurt. I did not touch my foot because I was freaked out. We sat there and waited for a little while because neither of us knew what to do. After about 60 seconds I felt a little "release" and my foot unflexed and I could move/feel it again. It still didn't hurt.

I did some lifting last night. This morning that ankle was painful when I woke up, and now that I'm loosened up it's still a little sore. I was planning a run today but I had better hold off

Any clue what happened there? It was extremely peculiar.