Huorn-dark

When the Ents roused their Huorns, those speaking and moving trees were capable of travelling from place to place at remarkable speed, as they did during the War of the Ring. As they went, their movements were shrouded in a strange darkness known as the Huorn-dark, so that a forest of Huorns appeared to move as if it were blanketed in a great Shadow. The nature of this darkness remains mysterious; even those who saw it could not say for sure whether they were looking at shadows or at mists.