Mount Matter-Horn is described in the Legend of Wishbringer as a mountain peak close to the spirits in the sky. A tenth century knight, seeking the hand of Morning-Star, attempted to climb the Mount to seek advice from the spirits, but instead fell to his death.

As the names of mountains are changed throughout the ages, it is not now specifically known which peak was formerly known as Matter-Horn, but in recent years scientists have speculated that this peak, as described in the Legend, would be as large as Mount Foobia, and may be the place where the Great Brogmoid standing on our world would place his other foot. If this is the case, it seems reasonable to conclude that Mount Matter-Horn would be located within the Mithicus Mountains on the opposite side of the world.