Smithers: I've got to find a replacement who won't outshine me. Perhaps if I search the employee evaluations for the word "incompetent." 714 names! Ha, better be more specific. "Lazy, clumsy, dimwitted, monstrously ugly." [The computer again displays 714 matches.] Ah, nuts to this. I'll just go get Homer Simpson.
Mr. Burns: Must call Smithers. He'll protect me from this beast. I've seen people activate this machine a thousand times. Doesn't seem to be any trick to it. Let's see, Smithers [begins dialing], S-M-I-T-H-E-R-S. Success, it's ringing!
Moe: Moe's Tavern.
Mr. Burns: I'm looking for a Mr. Smithers. First name: Waylon
Moe: Oh, so you're looking for a Mr. Smithers, eh? First name Waylon, is it? Listen to me, you! When I catch you I'm gonna pull out your eyes and shove 'em down your pants, so you can watch me kick the crap out of you! Okay!? Then I'm gonna use your tongue to paint my boat!
Answer: I'm not sure if this is the one you're thinking of, but an episode of "Ray Bradbury Theatre," called "A Sound of Thunder," dealt with a similar matter: a group of hunters travel back in time to hunt dinosaurs, only to find things have changed when they get back because someone stepped on a butterfly.
Xofer