Miss Quackfaster's Nephew is an anthropomorphic duck.
This teenaged duck is the nephew of Scrooge McDuck's secretary, Emily Quackfaster, who once took him to Tomato Soup Land. She later mentioned this to her boss, which inspired his short-lived attempt to turn in a profit from his Money Bin's sheer existence by turning it into a theme park called “Bin World“.
Miss Quackfaster's Nephew only ever appeared in the 2009 story Bin World. It is unknown if he is the younger brother of Maria, Miss Quackfaster's niece who debuted in an unrelated 2014 story, or if they are the children of two different siblings of Miss Quackfaster's.