6:26 071. Undertale (UNDERTALE Soundtrack) - Toby Fox 1:53 All of Undertale OST but it's the first note of every song 4:05 079. Your Best Nightmare (UNDERTALE Soundtrack) - Toby Fox 2:12 031. Waterfall (UNDERTALE Soundtrack) - Toby Fox 1:56 080. Finale (UNDERTALE Soundtrack) - Toby Fox 4:49 092. Reunited (UNDERTALE Soundtrack) - Toby Fox