Phoenix

The Phoenix was a magnificent, reddish-black firebird that was larger than an eagle, with a saffron chest, its head crested with scarlet, and its tail purple.

The Friends of Narnia encountered a Phoenix in a garden in Aslan's Country after Aslan ended the Narnian world. It roosted in the tree under which sat the thrones of Frank I and Helen, the first king and queen of Narnia.

Shortly after the creation of Narnia, Digory Kirke encountered a similar bird roosting in the Western Wild, in the Garden of Youth, where Aslan sent him to retrieve an apple. Although this bird is never called a Phoenix, both birds and this garden are very similar to the Phoenix and garden in Aslan's country, so it is possible that they are in fact the same bird and the same garden. The Phoenix along with the Garden of Youth likely vanished into Aslan's Country a week or so after the world was created.

Adaptations
In the Disney adaptation of The Lion, the Witch and the Wardrobe, a Phoenix was added to the Battle of Beruna scene. During the battle, the Phoenix was used to create a wall of fire; it was signaled by the launching of an arrow, which exploded. Jadis's black-bearded dwarf archers tried to shoot the bird down, but it dodged their arrows. A harpy also attempted to intercept the Phoenix, only to be shot down by a spear thrown by Peter, who also struck down any other members of the witch's army that tried to shoot the Phoenix.

The Phoenix was successful in creating the wall of fire, though it did not hold off the White Witch's Army for long, as Jadis used her magic to clear the fire from her path.

In the film, the Phoenix appears to have a forked tail, and can set itself on fire at will.

Links
Phoenix