Crotalus basiliscus is a venomous pitviper species found in western Mexico. The specific name is derived from the Greek word for king, basiliskos, and is an allusion to this snake’s large size and potent venom.

It is one of the largest rattlesnake species with specimens exceeding 150 centimetres (4.9 ft). The maximum size reported is 204.5 centimetres (6.71 ft) and the snake can be found in western Mexico from southern Sonora to Michoacán, where it is mostly restricted to the coastal plain. This species is known to produce large amounts of highly toxic venom and large specimens should be regarded as very dangerous. [Source: Wikipedia]