My 15-year-old calico does that if you look at her and put your arms up in the air. I'm not really sure how this started, but she's done it her whole life. Who can say whether we trained her or she trained us...?
It was cute. But I suspect the behavior be somehow connected with the mindset of 'give me what I want'. I know of many domestic cats that fall prone like that if they want human attention, or food from the human (a sort of begging - they seem to know that falling over and acting cute makes humans happy). So perhaps once the stalking didn't work and it flew away, the cat's brain initiated the fall-over as sort of a 'but I want it!' kind of thing.
But I suspect the behavior be somehow connected with the mindset of 'give me what I want'. I know of many domestic cats that fall prone like that if they want human attention, or food from the human (a sort of begging - they seem to know that falling over and acting cute makes humans happy). So perhaps once the stalking didn't work and it flew away, the cat's brain initiated the fall-over as sort of a 'but I want it!' kind of thing.
Then the loud laughing made kitty go "Gah!"