Gladiator

In ancient Rome, blood sport rules the mobs, or so we are led to believe in the epic movie "Gladiator" of 2000. The life of the loyal and successful general Maximus takes a turn for the worse as the emperor Marcus Aurelius chooses him as successor over his son Commodus. After the old emperor's death, Commodus has Maximus' family murdered. Maximus himself barely escapes with his life. As he gets trained as a gladiator, he finally gets his chance at revenge when he is sent out to Rome to entertain Commodus and the crowds. Maximus wins the favor of the crowds, and of some members of the senate of Rome. Commodus strikes back, and has several senators captured or murdered.
In the night, we see the soldiers of emperor Commodus put a snake in the bed of one of the senators who support Maximus. As senator Gaius and his mistress sleep, we see how a snake slithers between their bedsheets. The beautiful snake is brightly colored, and therefore must be quite dangerous. Animals that have effective means of defending themselves, such as a potent venom or a very bad flavor, often have bright colors (aposematic coloration). Luckily for senator Gaius and his bedfellow, the snake sharing their sheets is a harmless milksnake (Lampropeltis). These snakes are brightly colored because they are trying to pass as another species of snake- a highly venomous coral snake (several genera of the family Elaphidae). Not only a nice case of batesian mimicry in which a dangerous species gets mimicked by a less dangerous one, but also an observation of great historic interest; Apparently the Romans had already reached the new world way before Columbus or the Vikings! Not only had they reached the new world, but also brought back a pretty and harmless snake from North America.. Roma invicta!

The snake which looked dangerous.
The dangerous looker which came across the Atlantic.
The Atlantic crosser which did not kill anyone.