Macabra was originally designed to resemble Flaaffy.
For a short while, it was a proposed evolution of Dreamdery.
Macabra originally drew inspiration from the mythical creature Ao Ao, which is a "sheep-like creature that eats humans". The current design and concept is more inspired by the common English saying: "a wolf in sheep's clothing" now.
Though initially designed to hunt and wear the wool of Flaaffy, the design was quickly reworked to bear a more generic woolly appearance, and the rivalry between Macabra and Dreamdery was soon established.
Though not part of the initial concept, some similarities to the more commonly known Chupacabra (specifically its preying on sheep) influenced parts of the pokemon, such as its name.
Macabra's name is a combination of macabre and chupacabra.