Steve Hwang, a member of the San Francisco-based music and art collective Space Cowboys, on the group’s “Unimog,” as told to A.J. Baime.

The idea for the Mog first came in 2000, and a lot of the original inspiration was Burning Man (an annual gathering in the Nevada desert). We wanted to create an urban assault vehicle that plays music, a fully self-contained mobile sound and video system.

We...