When the Nocturnus Clan returned on Earth to escape from the Twilight Cage, the Nocturnus Clan set up signal projectors in Green Hill Zone that could control the native animals. As such, the Giant Scorpions and the other animals in Green Hill Zone became aggressive, and began attacking anyone who got nearby. In the side mission "Stop the Signal", Sonic and his team destroyed the signal projectors, resulting in the Giant Scorpions and all the other animals in Green Hill Zone returning to normal.
The Giant Scorpions can only be encountered on one occasion in the entire game, which is in Green Hill Zone. Here, a pair of Giant Scorpions were enraged by the signal from one of Dr. Eggman's old communicators, which a Little Boy that was playing with it, and the Giant Scorpions attacked the Little Boy. Before they could harm him, however, the Giant Scorpions were defeated by Sonic and his team.
In combat, the Giant Scorpions can perform two actions per round. Their basic attack is pinching their opponents with their pincers, which can deal two hits per use. Their POW moves is Tail Blast, which can inflict Poison and deal two hits per use.