Long Ears was about the size of a mule, with immense ears, a very hideous appearance, and a disagreeable odor; it caused a dangerous disease. Two colors of this creature are described: dark brown, and nearly black and slate color. The Oklahoma Seminoles described the being as gray, about three feet tall, with a head like that of a wolf, the tail of a horse, and enormous long ears. Like Tall Man [i.e., a giant], it was said to smell like stagnant muddy water. (Creation Myths of the Creek Indians [University Press of Florida, 2002] 36)

The wolfish head and comparisons with a horse or a mule lead me to wonder if perhaps some species of mesonychid (like the Sinoplotherium pictured above, but with long ears?) would be an appropriate stand-in for this creature, should it ever find its way into fiction.