Image imported from derpibooru
Original Description:

Appearance and Personality

A tall red pegasus with a black curly mane and brown eyes. His wings are made up of firey looking feathers similar to those of a phoenix. Similar feathers can be found in his pelt, particularly on his cheeks, shoulders, and haunches. When flying, particularly when flapping quickly, his feathers glint with flashes and light that give the appearance of sparks and fire. This effect shows in his flight trail as well.

World travel

Spark uses his phoenix essence to become composed entirely of flames, through which he can travel between dimensions. Upon entering the world through an existing source of fire, his body, still pure flame, shapes into a that of a being that would inhabit the plane he is now in. After solidifying back into organic material, the fire around his body disperses. When leaving a dimension, he ignites in the same way, then burns completely leaving a pile of ash where he previously was.