Gary Koopa is a Koopa in Dinosaur Dilemma. His name is a pun on "Gary Cooper," a prolific film actor. He is a member of the Snowbell Prize Committee, which had awarded Bowser the Snowbell Prize, and Bowser then invited the committee members, Gary included, to his summer home in the Valley of Bowser. He is first seen as Mario and Yoshi make their way into the fortress, although the narration does not provide any details about him. Later, as Mario and Yoshi are fighting Bowser and the Slimosaurs, Gary leads the committee to investigate the commotion. As the committee members enter the room, the Slimosaurs explode, covering the committee in a thick layer of goo. Disgusted, everyone quickly exits, with Gary exclaiming that this is an outrage.
In Brain Drain, Gary is briefly mentioned: When Mario, who is in the body of Princess Toadstool after swapping minds with her, claims to be himself, a nearby Magikoopa then claims to be Gary, "the famous turtle movie star."