So! It seems there's some treatment that can render one unkillable in a rather indestructible way. They had set up a thing to do some FDA testing of it, using volunteer subjects. After a treatment, the subject was pretty much unbreakable until they did something (or enough stuff happened to them) that would've killed them, had they not been treated, at which point they required another treatment to next cheat death.
One side effect of the treatment was that folks would gradually grow more and more beatific with each dose. Initially it wasn't much, but before too long their skin would start growing pale, their personality would take a turn for the stoned/zen, and their hair would start to blanch as well as beginning to drift about their heads, like they were slightly weightless. After more treatments, the pale skin would start to downright glow, they'd hover a few inches off the ground, and an invisible choir would sing a sustained note around them.
Usually when it got to the absurd later stages of the side-effects, the folks running the program would drop them from the testing, since glowing hovering folks accompanied by their own personal theme-music choir are a bit beyond 'baseline'. They'd give them $20 in severance, thank them, and send them on their way.
PS: Submitted this one to Slow Wave