Basilisk

In European bestiaries and legends, a basilisk (/ˈbæzɪlɪsk/, from the Greek βασιλίσκος basilískos, "little king;" Latin Regulus) is a legendaryreptile reputed to be king of serpents and said to have the power to cause death with a single glance. According to the Naturalis Historia of Pliny the Elder, the basilisk of Cyrene is a small snake, "being not more than twelve fingers in length," that is so venomous that it leaves a wide trail of deadly venom in its wake, and its gaze is likewise lethal; its weakness is in the odor of the weasel, which, according to Pliny, was thrown into the basilisk's hole, recognizable because all the surrounding shrubs and grass had been scorched by its presence. It is possible that the legend of the basilisk and its association with the weasel in Europe was inspired by accounts of certain species of Asiatic snakes (such as the King Cobra) and their natural predator, the mongoose.

Source: http://en.wikipedia.org/wiki/Basilisk