My personal ponysona Ember Eclipse: toyhou.se/594995.-ember-eclips…  
This is her nightmare form, “Nightmare Eclipse”
 
I don’t really have too many fears, and when I made this form, I had some serious anger issues. I guess I take fear and turn it into anger maybe? Anyway, I reckon that would be how to prey on any insecurities.
 
The form is fun, because my oc is an appaloosa (has spots, or a blanket that drips into spots) and the more corrupted she becomes, the more her spotted blanket spreads across her body (until she becomes solid deep maroon). This is also how she secretes the oil that ignites with her mane and tail.
 
She is able to manipulate her flaming mane, into a variety of shapes, and here her mane has produced makeshift wings. Her cutie mark is a jack of all trades sort of deal, so she is very flexible in her abilities. Unfortunately I’m an earth pony through and through so while I can be creative with her abilities, I often find myself limited in what I can do.