The Rat Monsters are minor villains who appear in the TV series the Mighty Morphin' Power Rangers. The Wizard of Deception transformed three rats into monsters while in Angel Grove's colonial past. The Green Ranger clone and the White Ranger return to the past and face the rat monsters alongside each other. After being defeated, they were turned back into regular rats by the White Ranger with the Wizard's wand.
The Rat Monsters in this episode were originally intended to be used in the feature movie which was being filmed at the same time. However, Haim Saban himself thought they were too low budget for a movie and used them here instead. Also, they are US-exclusive monsters.
NOTE: The Rat Monsters are US-exclusive monsters.