He is known for his underground comix character Mickey Rat, for popularizing the term "couch potato," and for being a member of Robert Crumb's band the Cheap Suit Serenaders.
Mickey was "sleazy, opportunistic, capable of just about any foul deed, but also shallow, one-dimensional, and incapable of growth or subtlety.
"[2] Mickey Rat #1 came out in 1972, also scripted by Crill and illustrated by Amstrong, and published by the Los Angeles Comic Book Company.
Over his career, Armstrong has contributed to many anthologies (many involving Mickey Rat), including Weirdo, Arcade, and Comix Book.
Armstrong has been a member of R. Crumb & His Cheap Suit Serenaders since the 1970s, performing vocals, musical saw, and guitar.
With three books and endless promotion through the 1980s, the Couch Potatoes appeared in hundreds of newspapers, magazines and broadcasts, spreading its "turn on, tune in, veg out" message, garnering 7,000 members, and popularizing the term.