The actors were filming a fight sequence when Malkovich jokingly asked Brolin to "pull his finger" during a fart joke, reports The Sun.
"I thought it was a joke, so I pulled his finger and I heard this click, and I was like, 'What was that?'" Brolin explained.
"And he goes, 'Um, I think you broke my finger. Anyway, I'll be fine, thank you', and then he walked away."
He added: "I was like, "Oh my god'. That was the strangest, most eccentric moment I've ever experienced in my life."
