"Sometimes the best way to deal with a mad man is to send in another madman..."
*On a plague of bird-eating lizards that ate all of Springfield's pigeons*
Skinner: Well, I was wrong. The lizards are a godsend.
Lisa: But isn't that a bit short-sighted? What happens when we're overrun by lizards?
Skinner: No problem. We simply unleash wave after wave of Chinese needle snakes. They'll wipe out the lizards.
Lisa: But aren't the snakes even worse?
Skinner: Yes, but we're prepared for that. We've lined up a fabulous type of gorilla that thrives on snake meat.
Lisa: But then we're stuck with gorillas!
Skinner: No, that's the beautiful part. When wintertime rolls around, the gorillas simply freeze to death.
— The Simpsons, showing this trope being done 4 times in a row.
Gray: We need more teeth.
"Set a thief to catch a thief."
—old cliched proverb