Scritchy-scratchy fictional noise instrument invented by twin Irish avant-garde composers from the 2015 art project Historical Documents of the Irish Avant-Garde by Dr. Jennifer Walshe.
The name comes from the Irish expression “ruaille buaille,” meaning hurly-burly, or a furore. Inspired by their youth growing up near a noisy shipyard, Irish twins Sinéad and Fiachra Ó Laoire built 17 different versions. "All are characterized by the use of bows to activate strings, and most exploit subtones, undertones and scratch tones."
One of their compositions is titled "The Death of King Rí Rá" (1910), for which an actual recording was made!
They were rediscovered in 1988 and appreciated by Sonic Youth's Lee Ranaldo.