Another look into the motifs of MLP by William Anderson. This one is set in chronological order of Twilight's life.

This motif is either the melody/chord as shown in the first clip or is the use of the glockenspiel, harp, and choir.

It evolves throughout the first three seasons of the show during big moments in Twilight's journey with magic. I think it represents her "magical potential" and culminates in her ascension as an alicorn in season 3, which is why we don't hear it afterward.

Overall, I think it is a beautiful, if not haunting, motif about Twilight's abnormal and somewhat terrifying magical abilities, which far surpass the average unicorn.

All credit goes to William Anderson, the background music composer for the show!

Episodes in order of appearance:
0:00 Season 1 Episode 23
1:18 Season 1 Episode 1
2:06 Season 1 Episode 2
2:36 Season 2 Episode 3
2:53 Season 2 Episode 2
3:10 Season 3 Episode 13