I just came across a new trademark recently filed 
by Moog Music. It is for something that is named “Mavis”. 
Described as:
Electronic components in the nature of low pass filters for musical instruments; Downloadable software for creating and editing music and sounds
Electronic musical instruments; Electronic musical keyboards; Music synthesizers
Here is the link. 
https://trademarks.justia.com/970/10/mavis-97010462.html