According to this video [0], it is not something of carbon that the elephant puffs, but a "puffball mushroom". I was very eager to believe in his words when I watched that yesterday. It was because that the day before, I had watched another video [1] of from that channel featuring something really similar that he calls "earth star fungi" this time, at 1:35.
Leaving his words aside, it also is much more believable to me that an elephant eats a puffing mushroom than charcoal.