This issue is a tie-in with the ongoing BUNNY series published by Harvey from 1966-1971 (with a belated final issue appearing five years later). The house ads and fan club pages are identical to those published in BUNNY. Hy Eisman was credited with the art in BUNNY. Although Bunny Ball is a featured character, ROCK HAPPENING highlights the fictional rock groups that were supporting characters in the BUNNY series -- The Soular System (loosely based on The 5th Dimension and Sly And The Family Stone), The Beagles (The Beatles), and The Marmalade Mirage (based on The Mamas And The Papas).