"I'm a performance artist," the fan -- identified as student Oscar Plomer-Roberts -- can be heard to saying in a YouTube video of the incident. "Can you help me with the completion of my next piece by punching me in the face?"
LaBeouf was understandably not keen to oblige.
The 29-year-old actor and two other members of his art collective were holed up in an elevator at England's Oxford University student union building for 24 hours over the weekend. The #ELEVATE project gave students access to talk to the star and his cohorts about anything they liked.
LaBeouf's fellow "performance artist" was more interested in action than talk, however.
"Do it. Don't be a p**sy," the Plomer-Roberts said after LaBeouf tells him he doesn't want to punch him very hard.
The student then says he'll settle for a slap instead. When LaBeouf again balks, the student reminds everyone that "this is the man who gave himself two scars [for a film]."
"I'll do it to myself but I don't like doing it to you, dude," LaBeouf responded. "I just met you."
Seconds later, the sound of a light slap can be heard.
According to Oxford's student newspaper, Cherwell, Plomer-Roberts, a first-year English student at Oxford's St. John's College, was motivated because he thought the star might be "bored," so he was looking for "weird s**t" to ask the Fury star.
ET followed up with the student via email to ask about the experience. He emphasized that LaBeouf came across throughout their 45-minute interaction as a “seriously nice guy.”
"I asked him to punch me, and he connected a sort of play-punch -- as a joke obviously,” Plomer-Roberts told ET. "Then I asked for a slap instead, because he was obviously uncomfortable with the prospect of hurting someone -- because, I might add, he's a really nice guy."
The star even posed for a picture in the elevator.
Plomer-Roberts said the idea came out of wanting to help LaBeouf alleviate some of the boredom of his marathon elevator session.
"He had been standing in that elevator all day and must have been bored by questions about acting, film, art, etc. So I thought it would be a welcome change to ask him something he wouldn’t have heard before, and judging by his reaction, it seemed it was surprising."
The student thought some of LaBeouf's hesitancy to hit him might stem from prior media coverage but said the actor was a "great guy" for going along with it.
There was one more surprise Plomer-Roberts had in store, though. His line about being a fellow performance artist -- that was a joke, too.
"The 'performance artist' thing was a sort of dig at Shia, because it sounds like some sort of crazy thing he'd do for the sake of 'art,'" he said. "But I meant it as a joke, and he had the sense to take it as one."
Well, it sounds like Plomer-Roberts might have a future in performance art anyway, because this attempt went over pretty well.