Music by Kevin MacLeod. Available under the Creative Commons Attribution 3.0 Unported license. Download link: https://incompetech.com/music/royalty-free/index.html?isrc=USUAN1100643

MacLeod's description:

Genre: Unclassifiable
Length: 3:57
Instruments: Organ, Percussion, Glock, Voice, clarinet, strings, tuba
Tempo: 70

This peculiar piece does have a story. If anyone would like to animate it, you'll have to bring your own script. Moderately large changes every minute or so. Accelerando at the end.
ISRC: US-UAN-11-00643
Dark, Eerie, Mysterious, Mystical, Unnerving 2009