"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.

"It was a market that had never been played to... Nobody had sung their song to them."

Said Peter Fonda in 2018, talking about "Easy Rider." He is quoted in his NYT obituary, "Peter Fonda, ‘Easy Rider’ Actor and Screenwriter, Is Dead at 79."

That movie was so important to us young Boomers, half a century ago.

In 1967, Roger Corman, then the king of the low-budget movies, directed “The Trip” from a script by an up-and-coming actor, Jack Nicholson. Alongside Bruce Dern, Dennis Hopper and Susan Strasberg, Mr. Fonda starred as a mild-mannered television commercial director who uses LSD for the first time and makes the most of it. “Easy Rider,” which he also produced, came two years later.

There was also LSD in "Easy Rider."

What did Peter Fonda say about LSD in his later years?

“For me, it solved a great deal,” he said. “However, I didn’t take it and go out running through the city looking at lights. I was very circumspect and lay down on a couch.” Luckily, he added, “I don’t have an addictive character, and nothing except pot stayed with me.”

There's also The Beatles connection:

His mother committed suicide in 1950, when he was 10 and Jane was 13. Less than a year later, Mr. Fonda shot himself in the stomach with a pistol. Interviewed by The New York Times decades later, he insisted that it was an accident, not a suicide attempt or even a warning. “You shoot yourself in the hand or foot if you want attention,” he said, “not the way I did.”

Years later, he talked about the experience with John Lennon, who was reportedly inspired to write the line “I know what it’s like to be dead” in the Beatles’ song “She Said She Said.”

Here's how Wikipedia tells it:

"Like many Americans, I am very impassioned and distraught over the situation with children separated from their families at the border, but I went way too far."

"It was wrong and I should not have done it. I immediately regretted it and sincerely apologize to the family for what I said and any hurt my words have caused," wrote Peter Fonda, admitting that it was "highly inappropriate and vulgar" to tweet "We should rip Barron Trump from his mother’s arms and put him in a cage with pedophiles and see if mother will stand up against the massive giant asshole she is married to."

I wonder where the pedophilia idea came from? The problem under discussion was the separation of children from adults and putting children in cages/"cages" with other children. If the idea was to give the Trump family the same treatment, parallelism would have Barron Trump in a cage apart from his parents and held captive with other children. Why introduce a new evil, pedophilia, which actually seems to be something the complained-of policy protects against?

What a strangely disordered mind was put on display! No wonder Mr. Fonda is sorry.