The white deer

Untill I can think of a cool name they are called WHITE/GHOST deer or caribu.

They're my creation. A species that is an obnivore deer and can turn into a ghostly plasma as it pleases. It's horns grow as soon as it's born(both the female and the male have horns, just not as large)and finish as soon as they reach teenagehood.
They are timid mostly, but dangerous, they're horns are always sharp and they are powerful creatures. Barely anyone hunts them for these reasons alone. Plus it's extreamly hard to kill something that can turn into an untouchable plasma form.
These creatures are also one of the fastest creatures known, which speed can match even the fastest horse kings in normal form and in plasma form it can move almost as fast as the speed of light.
Some natives capture them when they're fawns, so unable to plasma yet. Then raise and train them to be very reliable mounts.
A great Shaman, Auzura(FA version of myself) rides one of them, the beast is called, Ghosthoove.

Story, Image, and species (c) Megan B./Iowemuffins