there are 4 artists sharing the same name: 1) a Belgian post-rock band from Leuven:
http://www.myspace.com/musthcore 2) a hardcore band from New Haven
www.myspace.com/musthxct
They were active from February to June of 2008, played a dozen shows and put out a demo. Members are now active in other bands. 3) a Schizo-Metal band from Norway. From their MySpace:
"Musth is a periodic condition, characterized by, amongst other things, highly aggressive behaviour. Testosterone levels in musth can be as much as 60 times greater than in the same individual at other times.

Read more about Musth on Last.fm.