Most actors don’t get roles as series regulars. For every Ted Danson or Alyson Hannigan, there are hundreds, if not thousands, of actors who show up for a guest part and are never heard from again. This is expected — getting a paycheck and a screen credit is enough for some people. The lucky ones sign on for multi-episode arcs and get a chance to play a fleshed-out character for a few weeks, and the luckier ones parlay that into a larger career.

Then there are the luckiest ones — actors who signed up for a one-episode part and then became a series regular. These are rare beyond rare, and understandably so. Producers and writers aren’t going to mess up their creative process because one actor had a good showing. Sometimes, though, it’s undeniable. A combination of good fortune, good work, and just impressing the right people has led these actors to launch from what should’ve been throwaway roles into major characters.

Andrew Robinson only expected to play Garak one time in Deep Space Nine

Garak was introduced in Star Trek: Deep Space Nine as an outwardly simple tailor who was clearly more than he seemed. As the series went on, he became one of the most consequential characters in Star Trek lore, especially in the later seasons during the Dominion War. When actor Andrew Robinson signed on for the role, however, he thought it was just a one-episode part.

Robinson tried out for Odo and was one of the finalists before losing out to René Auberjonois. His audition still impressed, and he was called back for the role of Garak. "I didn’t expect my participation to go beyond that one episode," Robinson told TrekMovie.com. What he didn’t know was that Trek producers saw the episode as something of a chemistry test. Garak was introduced to give Dr. Bashir (Alexander Siddig) a storyline, and if it worked out, they’d bring the character back. Suffice to say, it worked out. Garak is a big part of many of Bashir’s best storylines, and he would go on to be a memorable character in his own right.

For Hot in Cleveland, Betty White only wanted to star in the pilot

One of the biggest selling points of Hot in Cleveland, TV Land’s first original series, was the presence of Betty White as Elka Ostrovsky. Released at the height of the Betty White mania that saw her host Saturday Night Live in 2010, Hot in Cleveland took the already bankable TV star and put her prominently in the advertising. In other words, it was a sure bet to make a reasonably popular series. This is all the more remarkable given that White had no intention of making more than one appearance in the entire series.

As she relays in her book, If You Ask Me (via Showbiz CheatSheet), White only signed on for the pilot. She made it explicit in her contract that it was a guest spot only, and she wouldn’t be involved if it got picked up as a series. "It was to be a one-shot only," she explained, "because my schedule was packed." When the show got picked up and more episodes were ordered, her agent pushed for her to accept. She loved the company, but she still felt she was overloaded and couldn’t take time to shoot a whole series. White then signed on anyway, saying, "I have the backbone of a jellyfish."

The iconic Steve Urkel was supposed to be a one-off appearance for Jaleel White

In 1989, Jaleel White was a 12-year-old child actor who was just about ready to abandon the "actor" part. Roles were drying up, and he wanted to play basketball, but he figured that he might as well audition for this weird "nerdy kid" role since he had braces anyway. That role was, of course, Steve Urkel on Family Matters. Even though Urkel would go on to become one of the most iconic and oft-quoted TV characters of the past three decades, the role wasn’t planned for longevity — he was originally going to be a one-episode guest.

White told Entertainment Weekly that he was just happy finding a role he could get, but he decided to have fun in the audition. He wore his dad’s glasses, raised his voice, and picked up a silly walk or two. The audition impressed, and Family Matters co-creator Bill Bickley said he determined Urkel should be a regular at the first cast reading, explaining, "When we sat there and saw this kid read that role in the body of the script, instantly, we wanted him to be a regular on the show."

Andrew Rannells went from one scene to series regular on Girls

Elijah Krantz first enters the Girls world early in season one. Hannah (Lena Dunham) discovers she has an STD, so she meets with college ex-boyfriend Elijah (Andrew Rannells) to tell him … largely because she thinks she got it from him. The conversation does not go well, though in fairness, nothing on Girls ever went well for Hannah. However, Elijah stuck around as a guest character before becoming a full-on series regular. He’s since been cited as one of the best characters on the show, something of a novel take on the "gay best friend" trope.

This wasn’t in the plans for the characters. In fact, the word "plans" pluralizes something much simpler. "In season 1, I was meant to come in and do one scene in one episode," Rannells said in an interview with Goldderby. "Then they kept on asking me to come back." Going from one scene to series regular easily makes him the record holder on this list.

Originally, Emily Bett Rickards wasn’t supposed to stick around on Arrow for long

Felicity Smoak was never destined to be a major character on Arrow. The character was plucked from obscurity, a minor character in a decades-old Green Arrow story, just to fill a small and specific role. But despite the odds, she became one of the most important characters in the series, a founding member of Team Arrow and Oliver’s counterpart in a will-they-won’t-they storyline. Few people were more pleasantly surprised by this than Emily Bett Rickards, who wasn’t supposed to get anything beyond a cameo at best.

Rickards told Refinery29, "As far as I knew, I was being signed for two scenes — one day of acting." She was excited enough about those two scenes, and then before she knew it, Felicity was a series regular. She attributes this shift to Stephen Amell speaking highly of her after their scenes to executives, as well as interested journalists who got screeners asking about her characters. Felicity has since gone on to appear in almost every other Arrowverse show, all after a two-scene contract.

Chiana could’ve been a one-off appearance on Farscape

In a show filled to the brim with striking character design, few stood out on Farscape more — both character-wise and physically – than Chiana. Her contrasting black-and-white colors clashed with her "noble thief" personality, and she quickly became a fan favorite. She went on to appear in every season of Farscape, which saw her gain new abilities and expand her backstory. Clearly the writers took a liking to her, since she was supposed to be a one-and-done.

According to the BBC, Chiana was only meant to stick around for one episode and possibly die at the end of the hour. This makes sense, given that her living-on-the-edge lifestyle and her conflicts with her own government meant an assassination or sacrifice would’ve been entirely in character. Actress Gigi Edgley’s performance, however, impressed producers, who decided to keep her alive and bring her back as a regular the first chance they got.

Abby Wilde impressed the producers on Zoey 101

Stacey Dillsen was Zoey 101‘s requisite Nickelodeon weirdo. Her oddball traits included an endless stream of bad luck, a lack of popularity, and an obsession with Q-tips. Her lisp and songs about sassafras tea were among the most memorable moments from the show. The character has also appeared on other Nick shows, including iCarly. This is all astonishing, given that Stacey was only supposed to exist for one scene.

Actress Abby Wilde told MTV News that she was only given three lines total and that was supposed to be the end of that. "I did my episode," she recounted, "and I guess I did okay because they told me they were bringing me back, and the next time I came in, I had a first name, and the next time I came in, I had a first name and a last name. Then one day I came in, and I had a bedroom. Then I did 31 episodes."

Kim Rhodes was just going to be a guest on Supernatural

Sheriff Jody Mills first showed up in season five of Supernatural after losing her son and fighting zombies. But instead of Sam and Dean driving off in the Impala and leaving her story behind, Jody stuck around and made appearances in the following ten seasons of the show, becoming a fan favorite. In other words, it was quite the meaty role for someone who was supposed to be just another guest spot.

Actress Kim Rhodes has confirmed that Jody wasn’t meant to last more than an episode. As she explained to Nerds and Beyond while promoting the final season, "Jody was just a guest star of the week." However, she implied that getting intense in her audition helped her get the part and, likely, a bigger role going forward. Sam and Dean are certainly happy she stuck around that long.

At first, Sherly Lee was just supposed to be a corpse in Twin Peaks

When David Lynch needed to cast the corpse of Laura Palmer for the Twin Peaks pilot, he decided to just get a local actress. After all, they were only going to need someone for a few hours to be wrapped in plastic and then maybe have their portrait taken. As such, he picked some girl named Sheryl Lee from around Seattle. But something about her performance as a corpse struck Lynch, who later had her come back and record a scene of her at a picnic. It was at this point he realized she was something special and had to bring her back.

In an interview with the Twin Peaks Archive, Lee recounts that Lynch contacted her months after the pilot and asked her to move to Los Angeles for more work. When Lee pointed out that Laura suffered from a mild case of "being dead," Lynch told her that they’d figure something out. That something turned out to be Maddy Ferguson, Laura’s nearly identical cousin, a key member of the show’s ensemble. After Twin Peaks was canceled, Lee went on to star as Laura in Fire Walk with Me and had a critical part in Showtime’s Twin Peaks revival. Not bad for a dead girl.

Jack Shephard almost didn’t survive Lost’s pilot

It’s impossible to tell the story of Lost — if it’s possible to retell that convoluted story at all — without Jack Shephard. He was the de facto leader of the castaways from the pilot until the end. He was the face of the show, and it’s the role that earned actor Matthew Fox his Golden Globe and Emmy nominations. This makes it all the more surprising that Jack, arguably the main character of the whole series, was supposed to die in the pilot.

TV critic Alan Sepinwall wrote in his book The Revolution Was Televised (excerpted on Grantland) that the pilot was planned a bit different than how it turned out. Jack was still a doctor who’d quickly emerge as the leader, but Kate was a normal woman worried about her fiancé who was in the back of the fuselage before the crash. Jack would’ve been killed halfway through the episode, forcing Kate to take charge. This was nixed after ABC studio head Steve McPherson argued to the writers that this move wouldn’t so much show viewers that "everyone can be killed" as it would teach the audience not to trust the writers. Instead, they gave the death scene to the plane’s co-pilot and gave Kate a more compelling backstory.

Believe it or not, Breaking Bad’s Mike was going to be a one-off appearance

Mike Ehrmantraut is the glue that keeps the Breaking Bad franchise together. More than Walt, Saul, or Jesse, Mike is the thread that connects everyone, as he’s involved with the cartel, Gus Fring’s operation, Saul’s business dealing, and any number of odd jobs. Even though his name isn’t in the title, he’s arguably just as much the main character of Better Call Saul as Jimmy. He’s even the guy who plants the idea of Alaska in Jesse’s head during El Camino. As such, it’s hard to imagine that one of the most instantly recognizable characters of 21st-century television was created as a throwaway character, but it’s the truth.

His creation starts with Saul Goodman. Well, more specifically, it starts with Saul actor Bob Odenkirk. Saul originally had a four-episode arc, and one of his planned duties was showing up at Jane’s house to clean up the place before the authorities arrived. There was just one problem. Odenkirk couldn’t make it to set one of those weeks because he was busy working on How I Met Your Mother. As such, the writers had to come up with a new character to act as a fixer on behalf of Saul. They threw together some guy named Mike, played by tough guy actor Jonathan Banks, not knowing that he’d go on to help define the series.