A goanna is any of several Australian monitor lizards of the genus Varanus, as well as to certain species from Southeast Asia.
Around 30 species of goanna are known, 25 of which are found in Australia. This varied group of carnivorous reptiles range greatly in size and fill several ecological niches.
The goanna features prominently in Aboriginal mythology and Australian folklore.
The goanna’s hefty tail can be dangerous when swung, much like a crocodile’s; small children and dogs have been knocked down by such attacks. Often, victims in goanna attacks are bystanders, watching the person antagonising the goanna. Alarmed goannas can mistake standing humans for trees and attempt to climb off the ground to safety, which is understandably painful, as well as distressing for both man and beast
Source : wikipedia – Goanna