In the old ‘50s sci-fi movie “Invasion of the Body Snatchers,” aliens replaced happy-go-lucky humans with their brain-dead, easy-to-control evil twins. The twins were grown in creepy, coffin-sized pods while the defenseless humans slept. You would go to bed human then presto-change-o, you wake up a pod person, part of some giant collective-hive entity.

You would look just like your old self, but in reality you are a zombie-like creature that’s doing whatever your alien overlords command you to do, which is mainly to talk stiffly without emotion and to walk as if you are just learning how. Aliens always get a big, unearthly kick out of this, and no one knows why.

Becoming a pod person is just about the worst thing that can ever happen to you – the possible exception being asking your cousin to be your prom date or accidentally sending your boss an e-mail addressed “To Whom It Might Concern” that explains why you are actively searching for other employment. Or saying a dirty word extremely loudly just as all other conversation stops.

I bring all this up because suddenly, my health club is full of pod people.