巴西利斯克（basilisk），又叫蛇尾鸡或者翼蜥，在希腊和欧洲的传说里，是所有蛇类之王，并且能以眼神致人于死。根据Pliny the Elder的Naturalis Historia，巴西利斯克是一种有剧毒的小蛇，其爬行过的土地会留下有毒的黏液，而他的凝视同样也是致命的。

关于巴西利斯克的形象，有三种不同的描述：巨大的蜥蜴、巨大的蛇或是一只三尺高、有着蛇尾巴和牙齿的公鸡。据说它的头上有法冠或皇冠状的羽饰，故被称为「国王」，一般把它定位在一种鸡身蛇尾的怪物（cockatrice）。关于巴西利斯克还有一个另人难以置信的传说，据说它是从公鸡所孵化的蛇蛋出生（和鸡身蛇尾怪的传言－由蛇孵化的鸡蛋－刚好相反）的。在中世纪的欧洲，巴西利斯克和公鸡的形象才慢慢重叠，Geoffrey Chaucer就曾在其著作Canterbury Tales中描绘巴西利斯克（其称之为basilicok）的样子。

In European bestiaries and legends, a basilisk (/ˈbæsɪlɪsk/ or /ˈbæzɪlɪsk/, from the Greek βασιλίσκος basilískos, "little king;" Latin regulus) is a legendary reptile 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, 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.