The principal villain from the 1990s children's show "Chip and Dale's Rescue Rangers". He was grey and purple, IIRC, and he was always planning some plan or another to add to his already vast wealth or already strong control over society and the flow of resources. He sure was creative.

A fat cat also refers to any person in a position of comfortable power, with gads of material wealth.

Too, a feline which is obese, but that is silly.