Comet Diver's Story.

The story of my OC, Comet Diver. She was born as a pegasus, and conscripted for Class-D duty after her parents were killed by a group of unreformed changelings, loyal to Chrysalis. During her first test, there was a catastrophic containment breach. In the Heavy Containment Zone, she killed an SCP-049-2 instance that was attacking Dr Sophia Light.

When they reached Gate A, Doctor Light managed to stop the guards from shooting Comet Diver. She was not able to convince them to let her go however, and she returned to life as a Class-D. As you could imagine, this was hard on her. So close to escape, freedom, only to fall at the last hurdle.

Despite this, she was very compliant and obedient to Foundation staff. Doctor Light and she became close friends. One day, she was brought for a test with SCP-212. It removed her mane and tail (which haven't grown back since) and fused a horn onto her head. After some brief tests, she was scheduled for termination, but Doctor Light wouldn't have it.

To save Comet Diver, Light fast-tracked the paperwork for her containment, and she received her SCP classification just in time.

Note: She is not an alicorn. She is just a pegasus with a horn fused onto her head. She has no earth pony magic, (which is confirmed to be very real after G5 came out) so she does not fit the definition.