Fifi is Mona's yorkie terrier and the secondary antagonist of the Rabbids Invasion episode Dueling Rabbids and later protagonist of Rabbid Doggies.

In Dueling Rabbids, she and Mona attack the first two rabbids, and then the third rabbid arrives with the redeemed Bob The Dog. Bob scares off Fifi and she runs away while Mona goes after her, pleading her to come back. In Rabbid Doggies, she attacks one of the Rabbids, and steals Bob's ball. Fifi was also one of the animals in Rabbid Test: The Animals. In the first round, she placed a block on the floor and barked at it. In the other rounds, she pooped, and Gina (Jessica) made John clean it up. Fifi also made cameos in Sticky Rabbid, An Intruder among the Rabbids, Rabbid Fetch, Runway Rabbids, the Pact of the Super Rabbids, Raving Alien, Dream on, Rabbid, and Rabbid Radar.