"Beetlejuice, Beetlejuice, Beetlejuice!"
@Betelgeuse_3 was a Twitter bot based on the “obnoxious, devious ghost named Betelgeuse” from the 1988 movie Beetlejuice.
The bot would respond to tweets that contain the word “Beetlejuice” three times, similarly to how the ghost is summoned in the movie.
It was permanently disabled some time in July/August 2015 after Twitter blocked it.