Originally conceived as Zack Morris's nemesis, A.C. Slater arrived to Bayside High as an army brat who could potentially thwart Zack's chances with Kelly Kapowski. Unlike Zack, who hated doing schoolwork and loved nothing more than pulling pranks and goofing off in class, Slater was a model student and loved sports. Many of Zack's worst offenses against Slater happened in the first few seasons of Saved by the Bell, after which they became best friends.

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Even as unlikely buddies, Zack found ways to make sure Slater never had game, by ruining his chances with potential dates and messing up important school assignments. Zack's careless behavior often forced Slater to retaliate, which only made things worse. Though the two were bros in anything concerning placing wagers and terrorizing Screech, the animosity from their initial meeting permeated their status as pals throughout the show.

Zack kills Slater's best friend

season 4 episode 23 of Saved by the Bell AC Slater and his chameleon Artie

During Best Friends Week at Bayside High, Slater introduces his best buddy — and it's not Zack. While his father was stationed overseas, Slater befriended a tiny chameleon named Artie, and the two have been inseparable ever since. Zack makes fun of Slater's relationship with his pet, but later gets forced to take care of it when Slater's out of town.

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Zack is more interested in helping Kelly with a speech assignment than making sure Artie gets properly fed and watered, and eventually is responsible for his death. He tries to cover it up with Slater, only to have to fess up once Slater overturns his bedroom looking for his buddy.

Zack sets Slater up to get caught in a stolen car

Season 2 episode 4 of Saved By the Bell when Zack sets Slater up for auto theft during Driver's Ed class

In the first two seasons of the series, Kelly Kapowski has an on-again, off-again relationship with Zack, which means that sometimes she's available for Slater's advances. This creates a competition that lasts until Slater decides that he really wants to be with the outspoken Jessie Spano.

In one notable episode, Zack sets Slater up during Driver's Ed class to steal the training car and get busted by Mr. Belding, all because he can't handle the thought of Slater getting his license first and taking Kelly for rides.

Zack frames Slater for a hate crime

AC Slater looking upset at school on Saved By The Bell

Slater finds himself an unlikely candidate in the Miss Bayside Beauty Pageant after all of his friends decide to sign up. He's not the only boy in the contest; Zack persuaded Screech to sign up first as a "gender hero," when in reality he just wants to win $50 for betting that he could help Screech beat Lisa.

When Screech has an accident and gets a shiner on his eye, Zack has to think fast about how to cover it up. He frames Slater for the "hate crime" attack, successfully ensuring Screech will get sympathy votes and Slater will get zero votes for battering Bayside's "trailblazer." It's a really ugly storyline.

They constantly antagonize each other

Season 4 episode 1 the fight between zack and slater that almost broke bayside over joanna

From the very first season, Zack and Slater have been frenemies, continuing to socialize in the same group but ultimately always willing to take every opportunity to ruin the other's reputation. Zack has always been threatened by Slater's athleticism and Slater has always been jealous of Zack's influence at Bayside High.

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From Slater's constantly jabbing at Zack and calling him "Preppy," and Zack trying to keep Slater away from his next conquest, they don't have a strong friendship built on trust, respect, and mutual interests.

Zack and Slater fight over the same girl

Zack and Slater go after the same girl in season 4 episode 1 of Saved By The Bell

When the senior dance is all anyone can think about, Zack and Slater decide to look for some dates. They both set their sights on Joanna, a new student at Bayside High who isn't familiar with just how competitive the two can be. Zack goes for an approach filled with bravado, while Slater eschews come-ons in favor of polite conversation.

Eventually they end up forced into asking her to the dance at the same time, and while she thinks it over, they engage in a serious of hijinks aimed at taking each other out of the running, the worst of which involves Zack making Slater out to be a mother-hating Lothario. It all leads up to the fight that almost broke Bayside.

Zack makes Slater abandon his dreams as a chef

AC Slater and Screech cooking on Saved by the Bell

When Slater demonstrates a real aptitude for the culinary arts in cooking class, Zack isn't happy for his friend, because he's made a bet that Slater can win the next wrestling match and it won't happen if Slater's too busy focusing on quiche.

When Slater won't do the match, Zack uses Screech to guilt him into participating, knowing full well if he doesn't Screech will get pommeled. As a result, Slater's quiche is ruined, which affects his grade.

Zack pretends Slater is dying to get with Kelly

Jessie And Slater In Saved By The Bell

When Slater's father has the opportunity to be stationed in Hawaii, he decides to leave the decision of moving up to Slater, knowing that his son has made some strong connections at Bayside High. Zack, recently jealous at the amount of attention Kelly has been paying Slater, decides to think of a way to influence Slater's decision in favor of the move.

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He tells his friends that Slater is dying of a rare disease, and that the only cure for it is at a clinic in Hawaii. He also tells them Slater is stubborn about seeking treatment and that the only way he'll go is if he thinks they all hate him. So Slater's entire friend-base turns on him at Zack's behest until he has no choice but to move.

Zack dates Slater's kid sister

Season 4 episode 16 of Saved by the Bell where Zack asks out Slater's little sister

When Slater's younger sister J.B. returns to town after a year living abroad, Zack is intrigued, having only remembered her as a dorky little girl. When he sees her again, she's transformed into a beautiful teenager whom Zack wants to score with.

He makes comments about her with Slater right next to him and invites himself along to Slater's wrestling practice in order to ask her to the Max for a romantic milkshake. Slater is forced to chaperone their date to the movies and actively prevent Zack from groping his sister in the backseat of his car. It never occurs to Zack how much he's violated his friend's trust by preying on his family.

Slater makes Zack look stupid

slater and zach on saved by the bell

Zack often lets his constant preoccupation with gambling and scoring dates interfere with his friendships, but Slater never misses a chance to make Zack look like a total moron, especially when it means he can teach Zack a lesson.

When Zack tried to convince the whole school Slater was dying of a rare illness, he went along with it just to make Zack feel bad. When Zack spied on Jessie's all-girls' slumber party and found out Kelly was violent "when she liked someone," Slater let Zack believe it by appearing in a wheelchair, even though Kelly made up the fib when she discovered Zack's surveillance equipment.

They constantly gamble

Zack Morris and AC Slater making a bet at The Max in Saved By The Bell

One of the running gags throughout the series is Zack's constant need to gamble and bet on everything from the day Mr. Belding's wife is going to have her baby to Slater's cool new leather jacket. One of their bets even involves the loser becoming the others' servant for a week.

After failing to pass the midterms even after trying (unsuccessfully) to postpone them by flooding the school, Zack is forced to be Slater's servant. In typical Zack fashion, he prank orders pizzas that Slater has to later pay for just to remind him that having Zack for a servant isn't all it's cracked up to be.

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