The name "giant lizard" makes it sound like a kaiju, but the animal is in fact at a realistic size, growing to an exhibited size of one meter. It keeps its "Giant" name when put in comparison to one of the character's heads, as that character swings the lizard above his cranium. Ootokage is a fanmade nickname which translates to giant lizard, like Oodako for the giant octopus and Ookondoru for the giant condor.
Once on Farou Island, the expedition team find the Giant Lizard while in search of King Kong. The Giant Lizard antagonizes the main characters while one of them comically spins the lizard above his head. Scared and surprised at the same time, they immediately kill the Giant Lizard with a firearm. It is after this distraction that they hear the roar of King Kong.
Do you like the Giant Lizard?