Question: Which guest musician from the American hard rock band formed on Long Island, New York in 1969 appeared on Step Back?
Sentence (from "Mountain (band)"): Best known for their cowbell-tinged song "Mississippi Queen", as well as for their performance at the famous Woodstock Festival in 1969, Mountain is one of many bands to be commonly credited as having influenced the development of heavy metal music in the 1970s.
Relevant evidence: No