The Dastardly Dormouse is a light brown and gray dormouse wearing red slippers and a red night robe with the words "Twinkle twinkle, little bat." written on it. They also wear white nightcaps on their heads. It is also notable that their blue eyes appear quite tired, as if they didn't get enough sleep the night before. Their weapons of choice are a light gray croquet mallet and croquet balls of various colors for long-range attacks.
The Dastardly Dormice lack the strength of their lagomorph counterparts, but they have the ability to yawn really loudly, alerting guards of an intruder's presence. If any guards are nearby, then they will come running. They can also send croquet balls flying toward the Cooper Gang for long-range attacks.