Was playing singleplayer last night and heard a strange song

[PsuPepperoni]

It was at night, it creeped me out and it had an actual baseline. it was fairly long, and i think it even had lyrics but i could not understand them

Does anybody know what this is?

 

[CaptainGinyu]

That sounds completely amazing but I have no clue what it could be.
I have heard really strange sound clips (about 5 seconds long) that sound different from animal & mob/ambient sounds.
It creeped me out because it was really quiet when it happened and it just hit nighttime.

 

[Jamesl2k5]

cool, can you attach the clip?