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=USUAN1100348

MacLeod's description:

Genre: Soundtrack
Length: 1:49
Instruments: Snare, Tenor drum, Tympani, Chimes, Gong
Tempo: 90

An all percussion tension-sustaining piece... More chaotic than symmetric, but enough repeated themes to keep it cohesive.
ISRC: US-UAN-11-00348
Dark, Suspenseful, Unnerving 2007