The name of the fictional poison in the Princess Bride is iocane powder. The protagonist of the book which was entitled the Princess Bride (which was written by William Goldman in the year 1973) and its screen adaptation (which released in the year 1987) is Buttercup.
When three outlaws named Vizzini (a short genius from Sicily), Inigo Montoya (an expert swordsman from Spain) and Fezzik (a giant Turk) kidnap Buttercup and hold her hostage at knifepoint, a mysterious man in a mask catches up with the trio of outlaws and challenges each of them to a fight.
The masked man then produces a vial of iocane powder, which is a type of fictional poison, and takes two goblets of wine behind his back. He challenges the arrogant Vizzini to guess which of the two goblets the iocane powder is in. The Sicilian cheats, loses the battle of wits and dies.
When three outlaws named Vizzini (a short genius from Sicily), Inigo Montoya (an expert swordsman from Spain) and Fezzik (a giant Turk) kidnap Buttercup and hold her hostage at knifepoint, a mysterious man in a mask catches up with the trio of outlaws and challenges each of them to a fight.
The masked man then produces a vial of iocane powder, which is a type of fictional poison, and takes two goblets of wine behind his back. He challenges the arrogant Vizzini to guess which of the two goblets the iocane powder is in. The Sicilian cheats, loses the battle of wits and dies.