Jerry Garcia of the Grateful Dead added guitar to a number of tracks on the Jefferson Airplane's second album -- Surrealistic Pillow; at the same time he found out there were at least two L.A. bands called "the Warlocks".
...And no wonder! Witches and Warlocks abounded (abind? abinded?) in Hollywood during 1967's Summer of Love. The Los Angeles County legislators had, amidst much fanfare, appointed Louise Heubner (Seduction through Witchcraft) the Official Witch of Los Angeles County, and U.C.L.A. was issuing Bachelor of Ceremonial Magic degrees!!!
Garcia was there ostensibly as "spiritual counselor", but actually to get between the volatile Jefferson Airplane's coolness and good vibes and RCA's New York A&R men, who were convinced that RCA only needed one artist -- Elvis -- and of course all the other artists were unimportant to RCA except to show that they weren't a "One Artist Label"...but everyone in the industry knew they were and still are.
Rick Jarrard says Garcia never played on the album, but I was right there in the studio, and here's the photo to prove it.
Shortly after this event, Ken Kesey called me to say that Garcia had been riffling through a Brittania Dictionary and suddenly looked up and said, "Hey, how about Grateful Dead?"
...and the name worked. "Mockingbirds", however, did not. We did a few gigs and then re-named ourselves several more times before leaving L.A. for more fertile ground.