灰野敬二
In November 2017, Sumac announced the release of a collaborative album with Japanese multi-instrumentalist Keiji Haino titled "American Dollar Bill – Keep Facing Sideways, You're Too Hideous to Look at Face On". The album was recorded in summer 2017 in Tokyo’s Goksound recording studio as "a series of unrehearsed, completely non-premeditated sessions" and was released on February 23, 2018.