Brat and Runt are the two main antagonists in CatDog episode, Harasslin' Match. Brat is Winslow's niece and Runt is Winslow's nephew.
They were both voiced by two special guest stars: Brat was voiced by Kathy Kinney, and Runt was voiced by Peter MacNicol.
Brat and Runt gets drop off by a black limousine for a visit with Winslow. Winslow starts training with Brat and Runt to harass CatDog, Winslow uses a whistle to make Dog go crazy. Brat and Runt starts to humiliate Window by tying the rope to a ceiling fan blade and spinning him around. Brat said that they did it for CatDog and steals Winslow's catchphrase. Winslow becomes depressed and starts to leave his home, which Cat becomes happy for Brat and Runt and later they start torturing CatDog. CatDog decided that they want Winslow back and goes visiting him at the Retirement Building for Harassers, Hecklers and Pests, CatDog convince Winslow to come home and put a stop to Brat and Runt, but Winslow refuses. When Winslow returns back to CatDog, he uses payback at Brat and Runt by using the steak to lure Dog into Cat's mouth and scaring Brat and Runt. After Winslow's confidence is restored, Brat and Runt leaves off on a black limousine in defeat. Winslow gets Dog into chasing the steak tied to a limousine and Winslow gets tied to Cat's wrist and Brat and Runt starts laughing at them.
Brat is a lavender female mouse with blonde hair and a red nose.
Runt is a green male mouse with orange hair and a blue nose.