Plus Size Mean Girls Karen Smith I’m A Mouse, Duh! Women’s Costume

So Fetch. So Furry.

Look, she may not know exactly how the weather works, but Karen Smith knew how to throw down a Halloween look. This Plus Size “I’m a Mouse, Duh” Costume brings the iconic moment from Mean Girls to life, complete with ears, attitude, and enough early-2000s energy to summon a Burn Book from thin air. It’s flirty, funny, and unapologetically extra—just like the queen of questionably accurate animal costumes herself.

It’s not just a costume—it’s a pop culture thesis.

Design & Details

This officially licensed set includes a black chiffon babydoll dress with a ruffled, elasticized top and adjustable shoulder straps for a custom fit that’s cute without compromising comfort. The satin ribbon belt ties at the waist however you like—snatched, flowy, or somewhere in between.

Underneath, the stretch bodysuit features its own adjustable straps and adds a sleek base layer that keeps the outfit from becoming a full-on wardrobe malfunction. And of course, it wouldn’t be Karen without the ears: the included headband features plush mouse ears attached to a faux fur-covered plastic base for that perfect “I’m totally a mouse, duh” finishing touch.

Iconic Energy, Adjustable Straps

This costume is a nod to one of the most quotable films of all time. It’s ideal for Halloween parties, movie nights, or any occasion where you want to channel your inner clueless icon. Pair it with heels, gloss, and a healthy lack of self-awareness, and you’ve got a look that’s timeless, hilarious, and 100% Karen-approved.