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=USUAN1100507

MacLeod's description:

Genre: Soundtrack
Length: 1:51
Instruments: Piano and bass
Tempo: 80

A slow dark piece featuring a piano, bass duet. Begins with bass, then immediately piano comes in. Piece has continuous bass with piano coming in and out. Finishes with prolonged bass note. 036
ISRC: US-UAN-11-00507
Dark, Eerie, Mysterious 2008