Vocal: Twilight Sparkle (sampling from her songs)
BGM: Matryoshka (マトリョシカ)
MP3:
MP4: (English sub)
(No English sub)
I used neither UTAU nor Auto-tunes. In order to make Twilight sing in Japanese, I extracted vowels and consonants from her songs and lined up/pitched them on REAPER. So it can be called word-splicing, I guess.