Members of Alice in Chains, Anthrax, Mastodon and Soundgarden have teamed up as the super group King Ultramega to pay tribute to Chris Cornell by raising awareness & funds for MusiCares.. ‘Rusty Cage’ is the first single released from King Ultramega, featuring Alice in Chains frontman William Duvall on vocals. MusiCares is a non-profit providing mental health, addiction recovery and emergency services to those in the music community.