Can be from any genre. Mine is when an acoustic guitar comes in towards the end of a song and totally changes or reframes the mood/energy (see "Money" by Widowspeak)
acoustic guitar comes in towards the end of a song and totally changes or reframes the mood/energy
The Stage by Avenged Sevenfold fits the bill. Especially if you watch the video along with the music, that song is just all around fucking great, to include the ending.