Duemouse

Duema Mouse was first introduced in Duel Masters Versus Revolution season of the Duel Masters anime series

Duel Masters Versus Revolution
He is a mascot of the newly opened Duemar Land, a Duel Masters theme park. He first appears in a parade and asked for a volunteer in a duel and the prize is curry buns. Katta Kirifuda volunteers himself to this duel. During the duel, his pitiful actions had gained the audience's sympathy and Katta's annoyance. Even though he gained an upper hand by preventing Katta's creatures from untapping with Miracle Star, Lord of Dragon Spirits, he got defeated by Katta's Evol Dogiragon. However, he gave Katta a menacing glare before he returns to his cheery self, showing no signs of this action beforehand, much to Katta's confusion.

Trivia

 * His first name 'Duema' means Duel Masters in Japanese terms.