Taeyeon has revealed a highlight clip and teaser images for "Nightmare".

In the teaser clip, Taeyeon waits for someone to wake up and walks away. "Nightmare" is a track from the Girls' Generation member's upcoming fifth mini album 'To. X', which is due out on November 27 KST.

Take a look at Taeyeon's "Nightmare" highlight clip above and teaser images below, and let us know what you think in the comments below.