***Sharp reports videos are revealing people simply collapsing, often after turning around as if they see a threat, and then they are fighting to keep that unseen threat away. They finish on the ground, exhibiting convulsions. ****
Sounds like an epileptic aura.
https://www.webmd.com/epilepsy/seizure-with-aura
What does an epileptic aura feel like?
Flashing or flickering lights, blurry vision, dark spots, partial vision loss, or seeing things that aren’t there. A feeling of deja vu, panic, or detachment. Hearing voices or buzzing, ringing, or drumming sounds. Unusual, typically unpleasant smells.
Possible! What is triggering it!
My son has epilepsy, and he turns his head and grabs at the air just like the people in some of those videos just before having a grand mal seizure.