"Dag Nab You, Die-rec-tor! You'll pay for this!"
I'm thinking of two villains who can holler back and forth.
     "Dag Nab You, Muskeetor! You'll pay double for this!"
They hate each other, but they aren't foul-mouthed like some of these new baddies.
     "Blast! Die-rec-tor, I'll have your head!"
They stand on opposite rooftops and shout back and forth.
     "Rats! There is no escape, Muskeetor!"
Until one gives up or gets sick of it.
     "You also cannot escape, Die-rec-tor! The End is Near!"
There are rules to this kind of thing, which cannot be broken.
     "I hope you came looking for death, Muskeetor! You've found it!"
The insults may never be personal, and no evil powers may be used.
     "Looking for it, Die-rec-tor? I brought it! For you!"
They are far too sophisticated to use evil powers on each other.
     "Muskeetor, you shall see the inside of a coffin today!"
So they stand on opposite rooftops and threaten back and forth, neither giving way.
     "Yes, Die-rec-tor! I shall see yours! At your funeral!"
At the end of the day, if no heroes have come to "stop the rampage of tyrrany," they go out for beer and pizza. I think that's the best kind of super villain.