Bratty and Catty (/ˈbræti/, /ˈkæti/) are a pair of vendors that can be found in an alley to the right of the MTT Resort. They are best friends, often saying the same lines or finishing sentences for each other (usually in the American valley-girl dialect), and both are big fans of Mettaton. They have several wares found from the Garbage Dump, including the Mystery Key.

Bratty is a tall, green alligator monster that wears a primarily pink shawl with yellow and blue details on the sides. She has yellow hair that flows into curls. She, like Catty, has a very heavy "stupid blonde stereotype" voice.