It has been one of my favorites for years, so you probably already know it:

Carol of the Old Ones MP3.
Web page.
Lyrics:

Look to the sky, way up on high
There in the night stars are now right.
Eons have passed: now then at last
Prison walls break, Old Ones awake!
They will return: mankind will learn
New kinds of fear when they are here.
They will reclaim all in their name;
Hopes turn to black when they come back.
Ignorant fools, mankind now rules
Where they ruled then: it's theirs again

( Stars brightly burning, boiling and churning// Bode a returning season of doomCollapse )

If you've read the lyrics so far: the music does justice to the words, and then some.