Carga Pesada
Carga Pesada( in english, "heavy cargo") was a TV-series that aired in Brazil between 29 april 2003 and september 2008. The plot was about two truck drivers, Pedro and Bino(played by Antonio Fagundes and Stenio Garcia) and their many adventures in the brazilian country.

é uma cilada, bino!
In the 10th episode of the first season, called "Companheiros", Pedro and Bino are chased by a group of thugs who stalk them in the road. later, the bandits mount an ambush faking a car accident. When Pedro and Bino arrive in the site of the fake crash, Pedro warns Bino of this trap(how he discovered it was a trap will live on as a mistery) by saying "É uma cilada, bino"(literally, it's a trap, bino).

the awkward look in the face of pedro, the strange electric guitar-like music in the background and the fact that the ambush didn't look like an ambush at all gave this scene an enourmous lol potential.
É uma cilada Bino became tremendously popular in discussion forums, and even made it out o the internet, becoming a catchphrase to warn one of a trap or a trappish situation. it is considered as the brazilian version of "It's a trap".
another variant is to use the sentence in pictures of sexy women, to underline that… well, it might not be a woman at all.