Swindle McSue was an anthropomorphic fox.
An ancestor of Chisel McSue and every bit as crooked as Chisel, Swindle lived in the 18th century. He ran a scam on Captain Seafoam McDuck (Scrooge McDuck's ancestor): he hired him to deliver a crate of horseradish to Jamaica and had him sign a contract of his own devising, the small print of which actually said that should the horseradish not be delivered, Swindle would be entitled to all of Seafoam's possessions. Swindle sabotaged Seafoam's boat (the Golden Goose) and actually succeeded in his dastardly plan, though Seafoam still escaped with a silver watch and his golden teeth, which was enough for him to start anew.
Behind the scenes
He first appeared in 1953 in The Horseradish Story in flashback.