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=USUAN1100333

MacLeod's description:

Genre: Soundtrack
Length: 1:03
Instruments: Orchestral - Bass, Glock, Cello

Double Basses and glockenspiel - with some cellos thrown in. Dark, dark, dark! This bit got removed from a soundtrack I recorded. I still like it! 044
ISRC: US-UAN-11-00333
Unnerving, Mysterious, Eerie, Intense 2006