Kieran Culkin claims responsibility for getting Mark Ruffalo high on an off-Broadway stage

At intermission, though, everyone seemed pretty chill about it. (Perhaps they would have been pretty chill about anything in the moment.) “I’m like, ‘I thought this was a good prank. I’m stupid. Oh my God, I’m so sorry.’ But actually, they loved it,” Culkin recalls. “Mark says, ‘I haven’t smoked pot in 10 years; the second half’s going to be so much fun.’ There was this other actor who had never smoked pot in her life. She goes, ‘Is this what being high is? This is lovely.’ And then Phyllis Newman comes in and goes, ‘I haven’t smoked pot since the 1960s. Thank you, darling.’” Everyone except the (presumably sober) stage manager, that is. “Then the stage manager comes stomping in and goes, ‘I don’t care whose it is, or what happened, but Kieran, give me the joint,” he says. “I sheepishly handed her the roach and she said, ‘Ruin your life on your own time.’” 

Funnily enough, Ruffalo has told this story before, back on an appearance on The Graham Norton Show in 2012. Either because he’s a gentleman, or maybe because Culkin wasn’t Succession-level famous yet, Ruffalo didn’t name Culkin as the culprit and just referred to a “naughty young actor.” Regardless, he had a pretty good sense of humor about it then, too. “The girl that I was passing it to had never smoked pot in her life,” he recalled. “I had, up to that point, smoked a lot of pot.”  

Years later Culkin did This Is Our Youth with Colin Hanks, and joked he would do the same thing to him. Hanks threatened to punch him in the face. But later in the run, he warmed to the idea, and when Culkin did in fact swap the fake weed with the real thing, Hanks apparently got so nervous he couldn’t even roll the joint. Aw! And thus ends Kieran Culkin’s experimentation with drugs.