"Death By Glamour (Beta Mix) - Undertale" is a high quality rip of "Death by Glamour" from the game Undertale.
This rip is a reference to Duane, one of the dancers from the 1989 direct-to-video film Barbie Dance Club who became a meme in the 2000's and 2010's after being used by notable Internet figures such as Vinesauce Joel and the website "Everything is Terrible!". The joke here is most likely a comparison between Duane and Mettaton, who are both known for their signature dancing and being "the star of the show".
This rip consists mostly of a mashup of the advertised track and the song "You Can Do It" by Adam Routh and Patrick Wilson, the song that plays as Duane performs his signature dance moves. Also around the beginning of the rip, an audio clip is played of the host of Barbie Dance Club, Dawn Merrick, shouting "Duane!" to introduce the dancer in question.
- Duane! - Know Your Meme