_photo via the_ “_Jerry Garcia Facebook page_”:https://www.facebook.com/jerrygarciaofficial/photos/a.182877411845314.44602.175343455932043/740409762758740/?type=3&permPage=1_

Fifty years ago today, Jerry Garcia, Bob Weir, Phil Lesh, Bill Kreutzmann and Ron “Pigpen” McKernan transitioned from The Warlocks into the Grateful Dead, playing their first show under that moniker in San Jose.

The performance came as part of one of Ken Kesey and his Merry Pranksters’ Acid Tests. The Pranksters were musicians themselves, and, according to Ken Babbs in a recent interview with Relix, the former Warlocks came and starting playing their instruments. Thus the Dead’s legendary relationship with the Acid Tests was born.

In the interview, Babbs goes on to describe more of the logistics of the Tests, which brought together the Pranksters and friends who were looking to experiment and educate. “There were two plastic trash cans in the middle of the floor with Kool Aid,” says Babbs. “And one trash can said, ‘For Kids: OK’ and the other said, ‘Adults Only: No Kids.’ We never knew or ever cared who did it, but somebody would fill the adult one with LSD.”