In Starwars: Return of the Jedi, during the assault on the second Deathstar, the Evil Emperor lures the
Rebel forces into a trap.
The Master of the Obvious, and Admiral of the Rebel Fleet, Admiral Ackbar exclaims "IT'S A TRAP!", after one of his subordinates says "Enemy Ships in Sector
47!"
This is fundamentally the greatest
Star Wars line, and one liner ever.
Usage is widespread.