Well-known actors who can attract attention or lend prestige to film projects can often command significant salaries. Jack Nicholson, for example, reportedly made more than $50 million for portraying The Joker in 1989’s Batman after merchandising royalties were factored in. But performers don’t always opt for money—or even feature-length movies—if a filmmaker is persuasive enough. Here are several notable talents who agreed to appear in obscure short films for a variety of peculiar reasons.

1. HARRISON FORD // WATER TO WINE (2004)

Arguably one of the most successful leading men of the 20th century, Harrison Ford has always been candid about his criteria for film work. In addition to being intrigued by a role, he wants to be compensated. (“No, I got paid,” he told a talk show host who asked if he was nostalgic about returning to the Star Wars universe in 2015.) He apparently made an exception for Water to Wine, a 2004 amateur film shot by a group of snowboarders in Wyoming. Ford—who has a ranch in the state—accepted the role of “Jethro the Bus Driver” as a favor to the filmmakers, who were friends of his son, Malcolm. Ford’s sole request was that his name not appear in the credits.

2. BRYAN CRANSTON // WRITER’S BLOCK (2014)

Breaking Bad star Bryan Cranston was shooting the feature film Cold Comes the Night in 2012 when Hurricane Sandy interrupted production. Rather than sit idle, the actor told the movie’s production assistants that if they wanted to try writing a short film, he’d shoot it immediately. Winner Brandon Polanco came up with Writer’s Block, a 13-minute black-and-white mood piece about an author wrestling with a lack of inspiration.

3. BILLY BOB THORNTON // THE LAST REAL COWBOYS (2000)

Billy Bob Thornton broke into Hollywood with his 1994 short film Some Folks Call it a Sling Blade that he later expanded into a full-length feature. That DIY approach may have helped director Jeff Lester entice the actor to star in The Last Real Cowboys, a short that featured Thornton as one of two main characters sitting next to a campfire. The production shot for just one day 50 miles outside of Las Vegas. 

4. OSCAR ISAAC // LIGHTNINGFACE (2016)

A year after Star Wars: The Force Awakens crossed $2 billion at the box office, Oscar Isaac (who portrayed Poe Dameron) appeared in this eccentric short by director Brian Petsos. Isaac is Basil Stitt, a man who gets hit in the face with lightning and is convinced he will soon develop supernatural abilities. Isaac and Petsos previously worked on a feature film, Ticky Tacky.

5. BENEDICT CUMBERBATCH // LITTLE FAVOUR (2013)

The BBC’s Sherlock helped make Benedict Cumberbatch a highly recognizable screen presence worldwide, which in turn helped this short film raise and exceed its $40,000 budget via the Indiegogo platform. Cumberbatch portrays a British intelligence officer active during the Iraq War who is contacted by an American spy to repay a favor. Cumberbatch, who was nominated for a Best Actor Oscar for The Imitation Game in 2015, also produced the film.

6. MICHAEL FASSBENDER // PITCH BLACK HEIST (2012)

Two-time Oscar nominee Michael Fassbender co-stars in this tight heist thriller about two thieves who are forced to complete a job in total darkness. (Liam Cunningham, who plays Davos Seaworth on Game of Thrones, co-starred.) Director John Maclean knew Fassbender before the actor broke out in 2009’s Inglourious Basterds and convinced him to take the gig. The two later worked on the well-received 2015 Western Slow West.

7. BILL MURRAY // A FILM ABOUT WALKING IN SLOW MOTION (2012)

The urban legends surrounding Murray’s puckish behavior are well-documented, from crashing karaoke parties to spontaneously tending bar. In 2012, Murray was filming a promotional video for a school in South Carolina attended by his son. Afterward, director David Smith asked if he could film Murray walking down a hall with crew members. He complied—and then kept walking, out of the building and into his car.