"Fonda kept insisting on telling people that he knew what it was like to actually be dead, in a misguided attempt to reassure George Harrison, who he wrongly believed was scared of dying..."

"... and insisted on showing them his self-inflicted bullet wounds. This did not go down well with John Lennon and George Harrison, both of whom were on acid at the time. As Lennon later said, 'We didn’t want to hear about that! We were on an acid trip and the sun was shining and the girls were dancing and the whole thing was beautiful and Sixties, and this guy – who I really didn’t know; he hadn’t made Easy Rider or anything – kept coming over, wearing shades, saying, "I know what it’s like to be dead," and we kept leaving him because he was so boring! … It was scary. You know … when you’re flying high and [whispers] "I know what it’s like to be dead, man."' Eventually they asked Fonda to get out, and the experience later inspired Lennon to write ['She Said, She Said']. Incidentally, like all the Beatles songs of that period, that was adapted for the cartoon TV series based on the group, in this case as a follow-the-bouncing-ball animation. There are few things which sum up the oddness of mid-sixties culture more vividly than the fact that there was a massively popular kids’ cartoon with a cheery singalong version of a song about a bad acid trip and knowing what it’s like to be dead."

From "Episode 139: 'Eight Miles High' by the Byrds" (on the podcast "A History of Rock Music in 500 Songs"). I excerpted something about The Beatles, but the episode is ostensibly about The Byrds. That said, there's also plenty about John Coltrane and Ravi Shankar. And Sonny and Cher.