The great Argon lizard is a giant-sized, tubbier version of an argon lizard. This crimson reptile is known for turning in a clumsy circle and using its powerful tail attack, which strikes all of its opponents simultaneously. It is also drops a rare gemstone called the "great big Argon heart" upon its defeat. Naturally, they originate from Argonia.
A great argon lizard first appears as a boss during Version 2, where one attacks Anlucia's amnesiac self on orders from Anlucia the Maluminary, though its attacks are blocked by a light shield that is unknowingly summoned by the seemingly defenseless girl. It is properly fought alongside 3 Pteranodons during a side quest to obtain an argon heart, since it is a material to make therapeutic drugs.
When the player has scouted 50 different monsters, whether or not the player still has them, synthesized them or released them, a great argon lizard will be received at the monster pen in the Albatross.