After completing the game twice I became so suspicious of the pause menu sound effect The sound is extremely distinct, and to me it sounds exactly like someone using a water bong.

I tried to rationalize it as coincidence and came up with this. During development it was decided that entrance to the pause menu needed a good sound effect. Someone felt that "Bubbles" was would make a great effect to compliment the games pause menu, not because it sounds like a water pipe but for some other reason.