The Curious Quartet is the group name of Skeletor's four "finest warriors" in the 1987 film, Masters of the Universe. It consists of Blade, Saurod, Beastman, and their leader, Karg. They are given an individual villain introduction, and are totally inept at everything. Skeletor actually disintegrates Saurod after they fail to retrieve the cosmic key or He-Man on Earth.
Since Episode 15, the hosts have periodically used this term to refer to any group of four characters (typically villains) thrown together on screen nonsensically.