I inadvertently spun a JP Mk3A from a stall turn in 1977. Aircraft flicked, then went high rotational, something I hadn't seen before.
I lost 10,500 ft and recovered below the minimum abandonment height for the ejector seat. I wasn't a happy young pilot as I considered myself very lucky to get away with it.(Just wish I had a video of it to show my kids).
Didn't do it again and now my stall turns are spot-on!
I also had a Cessna 150 Aerobat go into an inverted spin from a normal entry. It was later found to have the wings rigged at different incidences.
ShyT