Maize is an Australian shepherd who is Marmaduke's main love interest. She also has a mix of Bernese Mountain dog in her.
Marmaduke first met Mazie at the dog park along with Giuseppe and Raisin. She shows him the park and explains that the dog park is like high school for dogs. She later invites him to a party, which he accepts but later suggest to crash Bosco's party, despite being for purebreds only. After Marmaduke is humiliated by Bosco, they leave the party, only to have a surprise encounter with Chupadogra.
Later, wanting to impress Bosco's girlfriend, Jezebell, Marmaduke pleads for Mazie to show him how to win a girl's heart. Despite her newly developed feelings for him, she reluctantly agrees.
Using Mazie's advice, Marmaduke and Jezebell bonds, much to Mazie's dismay. Later, Marmaduke throws a party while his family is away. Mazie, Giuseppe, and Raisin however, were not invited. Then Bosco crashes the party and exposes Marmaduke for being a liar, leaving him with no friends and no girlfriend.
Later, Marmaduke tries to see Mazie. However, Raisin and Giuseppe reveal Mazie's feelings for him leading him to look for her.
When he finally finds her, they both fall into a sewage system where Marmaduke saves Mazie.