Original 1st printing 14&1/8 x 20" concert poster for Texas psychedelic/fuzz rock legends the 13th Floor Elevators (with Roky Erickson) along with Quicksilver Messenger Service appearing at the Avalon Ballroom in San Francisco, CA on 9/30-10/1/1966. Art by Stanley Mouse & Alton Kelley, image ("Zebra Man") is # 28 in the Family Dog/Avalon series. Medium-thick flat vellum stock poster is in excellent to near mint (B+ to A-/B+) condition; a small 2" diagonal bend in the top right corner, a tiny bump in the top left corner, a stray pinch ding or two and slightly off-register printing on the pyramids at the bottom, otherwise an absolutely eye-searing example of the 1st printing Zebra Man poster with a VERY pronounced gradation of dark to light orange... a killer specimen of one of the most psychedelic posters of ALL TIME.