Trick and treat

Trick and Treat is a halloween song composed by OSTER-project, and illustrated by Y-ojisan.

It's one of OSTER-project most notable works; and was performed in the Vocaloid concert "MikuPa Live in Tokyo". It also has reached 1 million views in Nico Nico Douga.
 * Nicovideo Broadcast
 * Youtube Broadcast (with subtitles)

Background
The song was first uploaded on October 30th 2008; it's OSTER-project's first work using Kagamine Rin and Kagamine Len (duet) in a song. The song was uploaded for Halloween, OSTER-project's style is usually "cheerful" and "colorful", though trick and treat was her first work to be "dark". trick and treat reached 1 million views on November 21st 2011; making it the first Kagamine duet song (Gekokujou being the first song) to have reached 1 million views.

trick and treat basically tells of a story of "you" who were led by Rin and Len to a deep, deep forest. Although they seemed friendly at first, "you" realized things were not as it seems.