Can't you just see it? A horror movie where seemingly normal people just start doing Tai Chi, then they creep towards you to try and eat your brains. Hollywood, are you listening?
It is going to need a cause. The disease thing has been overdone. An electronic, cellphone-activated brain re-wiring app, perhaps. But for the deep chill down the spine, it should be caused by political indoctrination. Government hypnosis conspiracy using Tai Chi to eat people's brains. Dang.