Fission

            "Congratulations on your promotion, Atomic Flash!" Fluttershy  told my joyously as soon as I had told her the good news about my promotion yesterday.

            "Thank you Fluttershy, that's very kind of you." I reply as I lead her back down to my basement laboratory.

             "Kind of me? Oh no no It's very kind of you to keep my secret for me like this." She tells me in a very grateful tone. We are in the laboratory now.

             "You know the routine." I tell her. She smiles and lays down on the bench. "Open wide." I tell her. She opens her mouth and it all looks normal. "Extend out." I tell her sternly. Two of her teeth extend into fangs. "Good, now retract." And she does. "Alright." I say and levitate an apple over her nose with my magic and look at her teeth. Nothing happens. "Good job Fluttershy you didn't extend out that time!"

            "Yeah!" She exclaims weakly. I then levitate a scalpel over to the apple and cut it. Fluttershy's fangs still didn't show.

            "Do you feel any particular attraction to apples at all now Fluttershy?"

            "No I think that spell you came up with fixed it Atomic Flash."

            "I didn't come up with it, it was in Twilight's spell book. I think it didn't work completely when twilight used it because you where mildly distracted by the juice from the apple." I explain to her. "Look I went to Luna a while ago to get permission to explain something to you." I tell the pegasus.

           "Is it why I am this way?"asked Fluttershy.

           "I think so, Fluttershy.. Does your family have a history of guard traditions?"

             "Yes, most pegasus families do." She explained to me.

             "Well do you remember the two guards on nightmare night pulling Luna's chariot?" I asked. "Yes, I think so.. They where kind of batish weren't they?" She asked.

               "A long time ago, when Luna was preparing to rise up against Celestia, she transformed some of her pegasi guard by fusing their essence with that of bats to create better nocturnal warriors. A few escaped after Nightmare Moon's defeat and had children and their descendants still carry the gene." I explained.

            "So you think I have the gene? Why haven't I heard of any bat ponies till now?" Fluttershy asked timidly.

             "Nightmare Moon's presence triggers the gene and only three carriers are known right now, those two guardsman, Fang and Claw, and you. You did not realize you had the gene because you never really knew how to access your transformations, until Twilight cast her spell to make you think you are a vampire fruitbat." I concluded.

         "So all of those changes I went through I can do willingly?" She asked.

        "Yes, but each change will make you slightly more aggressive for as long as it is active, and you will feel weakened and nauseated in strong sunlight." I warned her.

         "For today we will start with the eyes which will give you night vision. Try to zoom in your vision" I asked her.

          "Okay, I'll try." She replied. Her eyes went a little red then stopped.

          "Try it again, you can do it!" I say trying to motivate her.

          "I really, really, can't." She said in a frightened tone."I don't what to be a vampony!" She cried out in protest running back up stairs.

           "Fluttershy, your not a vampony!" I called after her. Damn it! I should have been more gentle with her! I hope I didn't get her too scared...