Tremor
Just hit by a Very Random memory. When I was pregnant (many years ago) on of the things I was supposed to be doing was 'kick counts' where I'd count how many kicks or movements I felt in an hour. This was supposed to make me aware if there was no movement for a worrying amount of time. However. Kick counts, for me, were impossible. My daughter seemed to be moving all the time. In fact, sometimes I could feel my whole belly vibrating with unbelievably rapid movements. I couldn't imagine what was going on in there.
Finally my little bundle of joy arrived. She was pretty active, all right. But one day, shortly after her birth, my husband was holding her while she slept. And in her sleep she proceeded to have leg tremors. I mean just twitching and kicking up a storm. Didn't even wake her up. A-HA! I told him, I told you something weird was going on in there!
Fortunately, the tremors tapered off rapidly, and never created any problems for her. But, damn. That was a feeling, for sure.