As Phil Lesh noted in his 2005 memoirs, Searching For The Sound: My Life With The Grateful Dead, “We were at the first Acid Test not to play, but just to feel it out, and we hadn’t brought any instruments or gear.”

https://liveforlivemusic.com/features/grateful-dead-acid-test-1965/  The band members in attendance did eventually pick up some Prankster instruments and mess around. As Ken Babbs, Kesey’s Prankster lieutenant and host of the fateful party, recalled to Rolling Stone in 2015, “I remember the band, the guys who later became the Grateful Dead, showing up and playing on our instruments … and us playing on our instruments, and [Neal] Cassady being there and [Allen] Ginsberg and [novelist] Bob Stone and being up all night lying on the floor with microphones rapping stuff into tape machines until dawn.”

Today marks the 53rd anniversary of the first time the Grateful Dead, still known as The Warlocks, attended one of Ken Kesey and the Merry Pranksters‘ Acid Tests, where like-minded individuals would take LSD and enjoy “permissive bedlam” and untethered visual and, eventually, musical displays. This was the first Acid Test opened to the public, and the members of the Warlocks attended not necessarily to perform, but rather to check out the scene. However, the Warlocks would soon become the Grateful Dead, the Grateful Dead would soon become the Tests’ house band, and the weekly gatherings would become the training ground that allowed them to evolve into an improvisational force the likes of which had not been seen before.