Sheath your sword; do not smote this beast. 'Tis no mythic fire-breathing devil-substitute from the Middle Ages, but a simple Australian Water Dragon. On the fight-flight axis, it is most certainly the latter that he will employ if you take one step closer. He will lift himself high onto four legs and scarper comically through the underbrush where he camouflages excellently.
Australian Water Dragon (Physignathus lesueurii), found on the east coast of Australia from Victoria north to Queensland. They are fast runners and strong climbers. When threatened, they seek cover in thick vegetation, or drop from an overhanging branch into water. They are able to swim totally submerged, and rest on the bottom of shallow creeks for up to 90 minutes, to avoid detection.