Well, they may not be folk but I can recycle some suggestions from a previous Hallowe'en thread:

When you grow too old to scream (I'll have you to dismember)

Hey there (You with the bolt through your neck)

for plastic surgeons:

I'd grown accustomed to that face

and for cloners:

I want a girl just like the girl that married dear old dad

And one that would really suit most medical students:

I want a blow-up doll that I can call my own,
the one the other fellows cannot steal
[when I get home at night I will inflate her...]

If I ever have to go to hospital, I was only joking, guys!

RtS