The Night Series, known on Niconico as the SAM Night Series (SAMナイトシリーズ), is a series of Eurobeat songs by samfree. The songs are characterized by sharing the same pattern or rhythm, a similar title style (the VOCALOID's name repeated two times, a star and a catchy phrase with the word "night" in it), and a release date shortly after the debut of a new VOCALOID. In fact, it's almost a tradition for some of the newly released Japanese voicebanks to receive a song, as a sort of welcome.