
Ten years before For a Few Dollars More, Eastwood appeared in a decidedly minor role as a lab technician in the first sequel to the cult classic, Creature from the Black Lagoon. Eastwood gets a few choice lines near the beginning of the film such as: "I've lost my white mouse." Ironically, Eastwood's film debut is about the only thing memorable about this ultimately mediocre monster flick.

"Try as they will, and try as they might, who steals me gold won't live through the night!" A year before "Friends," Aniston turned in a totally forgettable performance in this critically panned horror film about a psychotic leprechaun (Warwick Davis) who embarks on a killing spree during his search for a pot of gold stolen from him. Believe it or not, Leprechaun has spawned a total of five sequels, including Leprechaun: Back 2 tha Hood [2003].

Amid all of the notable actors who appeared in Animal House—such as John Belushi, Tom Hulce, Stephen Furst, Donald Sutherland, Karen Allen and Tim Matheson—Bacon is usually forgotten for his quality performance as one of the asshole pledges of the Omega House. However, this movie later provided a gold mine for fans of the Sixth Degrees of Kevin Bacon trivia game.

In her first major screen role, Moore plays the heroine of this ridiculous, dystopic horror/sci-fi film, which was billed as "The First Futuristic Monster Movie in 3D!" Parasite also stars Demi's first husband, Freddy Moore, who also wrote the song, "Show a Little Emotion," for the film's soundtrack.

Don't blink or you may miss Vaughn's film debut as a Notre Dame football player in the true-life, feel-good story of a perennial underdog (Sean Astin) whose dream is to play football for the Fighting Irish. While filming Rudy, Vaughn met Jon Favreau (D-Bob), who would later costar with Vaughn in the cult movie, Swingers.

Depp portrays a victim of Freddy Krueger in this highly popular slasher film, followed by another lame performance as "Jack" in the teen sex comedy, Private Resort. Honorable Mention: Tom Hanks as "Eliot" in He Knows You're Alone [1980].

Hopper played a minor role as gang member "Goon" in the shadow of his idol, James Dean ("Jim Stark"), in this classic anthem of teen angst and rebellion. The two young and gifted actors would again appear together in Giant, Dean's last film.

In his first appearance in a mainstream film, Sylvester Stallone can be seen in an uncredited role in Bananas – one of Woody Allen’s early, funny films – as one of two subway thugs beating up an old lady. Terrified consumer products tester Fielding Mellish tries desperately to avoid getting involved in the conflict (he even hides behind a newspaper and kicks away the old lady’s cane!). Prior to his nonspeaking role in Bananas, Stallone appeared as "Stud" in the low-budget porno film, Party at Kitty and Stud’s (1970), as an extra in Lovers and Other Strangers (1970) and as "Jerry Savage" in No Place to Hide (later rereleased as Rebel). Stallone’s big break came in 1974 when he starred with Henry Winkler as gang member Stanley Rosiello in the underappreciated cult movie, The Lords of Flatbush. Honorable Mention: Jeff Goldblum as "Freak #1" in Death Wish [1974].

In his first-ever screen role, Newman turns in a totally wooden performance as a craftsman commissioned to create a silver chalice to protect the Holy Grail. Before this turkey was televised in the 1960s, Newman personally took out an ad in a Hollywood paper apologizing for his wretched performance in the film and requesting viewers to find something else to watch. The Silver Chalice also starred Virginia Mayo as "Helena," Jack Palance as "Simon the Magician" and Pier Angeli as "Deborra."

Before reaching superstardom as "Tony Manero" in Saturday Night Fever and "Danny Zuko" in Grease, Travolta starred as one of the Satanic cultists in this execrable low-budget horror film that also stars none other than Ernest Borgnine, William Shatner, Eddie Albert, Keenan Wynn, Ida Lupino, Tom Skeritt and Anton LaVey as the "High Priest." Travolta, who is covered with so much makeup as to be unrecognizable, melts away with most of the rest of the cast at the film's conclusion!
How about Mel Gibson in Mad Max? I'm no expert so maybe he was in a film before that, but it was definitly an unexpected rocket to superstardom. Props to "paul logasa bogen" for the James Earl Jones comment.
nick cage in fast times at ridgemont high
"inauspicious" is negative, as in their performance was kinda bad and they may not have much of a career ahead of them. Not the case for Mel Gibson, Robert Duvall, James Earl Jones and Rosario Dawson. In fact, Kevin Bacon should not be on this list...he was brilliant in Animal House.
Tobey Maguire in the late 80's/early 90's movie the wizard. He didn't have any speaking lines he was just part of Lucas's posse.
Billy Zane in Back To The Future. He is in Biff's gang.
Daniel Day Lewis in Gandhi
Seth rogen in donnie darko
John Cusack - Class - Roscoe Maibaum, 1983 Bruce Willis - The First Deadly Sin, Man entering diner - 1980 Dennis Hopper - Goon - Rebel Without a Cause - 1955 Kurt Russel - It Happened at the World's Fair - Boy who Kicks Mike - 1963 On a side not he played the Jungle Boy in Gilligan Meets Jungle Boy season 1 episode 19...Gilligan's Island
I got a twofer that beats em all: Matthew McConaughey and Rene Zellweger as the two main characters in Texas Chainsaw Massacre 4.
Nathan Fillion in Saving Private Ryan
Richard Dreyfuss in The Graduate; Gene Wilder in Bonnie and Clyde.
How about Gilda Radner playing an improv actress performing at the hippie party in "The Last Detail"? That was her movie debut. Also, Carol Kane as the whore, and Randy Quaid as the young prisoner in the same movie. Or Christopher Guest in "Death Wish" as the young cop talking to the detective at the end of the movie. Those are some I bet most people never thought of.