Megalania ("ancient great roamer", often mistranslated as "ancient giant butcher") is a large genus of monitor lizard, or goanna, from the Pleistocene period of Australia. It was the largest predator on the continent at the time, able to hunt whatever it wanted without much competition. Its most powerful weapon was its venomous bite, which allowed it to bring down even the largest prey without expending too much effort. It is believed by some cryptozoologists that Megalania may still exist today, however this is highly unlikely.
In The Land Before Time
Megalania briefly appears in one of the minigames of the game The Land Before Time Animated Moviebook.