It resembles a small stubby legged dog with the ears of a cat.
It gets its name from the sound it makes, which is akin to that of a boiling tea kettle. It only walks backwards (apparently by choice) and steam emits from its mouth as it makes its whistle. Only a few lumberjacks claim to have seen one, as the creature is so shy, but if a boiling kettle is heard and nowhere to be found, it could be that a Teakettler is nearby.
An account is given by Jorge Luis Borges under "Fauna of the United States" in the Book of Imaginary Beings, a book that contains 120 mythical beasts of folklore and literature.