Maybe it could be
Hiccups
It knows no mercy, spares no man
Everyone gets them at some point
Spawn of the devil 'tis
Some cultures claim hiccups are caused by the devil
It won't depart except by whim
Yields not to tricks or pleas
They're very difficult to get rid of even with many attempts, then suddenly gone. Most traditional tricks, like attempts at frightening someone, don't work out.
None know its provenance or purpose
Though theories abound
There's no agreed-upon scientific purpose for hiccups, but many potential explanations.
Hilarity will oft ensue
In places where it's found
Yep. Just ask anyone who's gotten hiccups in a classroom setting. Pandemonium.
A cruel fate awaits those whom it strikes
Though usually they'll live
Discomfort, shame, and helpless rage
Are their lot to receive
This pretty much says it. Generally non-fatal, of course, but definitely they cause discomfort and helpless rage, and possibly shame as well depending on context.
So next time you meet a poor soul afflicted
By its strange effects, take stock
Today it's him, tomorrow - you
Be gentle, do not mock!
Really, you don't want to mock people for having the hiccups, since you're just as susceptible as they are and you don't want to get your hiccomeuppance.
