One of the lasting legacies of Buffy the Vampire Slayer is the Big Bad formula. Each season was structured around one ultimate threat, like Mayor Wilkins or Glory, that would loom over every episode, even when it wasn't actually present.

But Joss Whedon and company didn't slack off when it came to the little guys, the monsters that showed up for just one episode of the show, and were never heard from again. While Buffy's greatest battles were usually between her and a long standing character viewers loved to hate (or just plain loved), there are some cool figures who stepped into the ring with the Slayer for one night only.

Below, in order of appearance, are the best villains, specifically demons and other non-vamps, that Buffy encountered for just one episode. They were judged based on how terrifying they looked, the craftiness of their methods, and the emotional toll they took on our beloved Scoobies. The best excelled at all three.

15. Ted - "Ted"

Ted serves as a perfect emblem of Buffy's metaphorical intent. When her mother starts dating a new guy, Buffy becomes cautious of the man like any daughter of a divorced parent would. Granted, Buffy's concerns are deep-seated ones planted by her Slayer occupation, but her worries are totally relatable on a human level, as is the loneliness she feels when Ted appeals to everyone except her. At least for a little while.

After making multiple threats to Buffy behind everyone's back, and eventually slapping her across the face, Buffy finally fights back by pushing him down the stairs. Luckily, Ted is a killer robot and Buffy's suspicions about him being dangerous turn out to be true.

Ted is campy in the style of early Buffy, and in that that respect he's enjoyable. But what makes Ted stand out is the real fear he represents, something that speaks to Buffy's primary conceit.

14. Der Kindestod - "Killed by Death"

Translated from German, "Der Kindestod" literally means "the child's death." True to its name, Der Kindestod preys on the lives of sick children, intentionally making their deaths look like a result of their ailments rather than his nefarious, life-sucking powers. If that wasn't horrifying enough, Der Kindestod is visible only to children with a high fever, so adults attribute his victims' fears to their illnesses. One of these victims is a young girl named Celia, Buffy's cousin.

A commonly forgotten person in Buffy's backstory, Celia acts as one of the formative elements in Buffy's hero complex. As kids, Buffy and her cousin play games in which Celia pretends to be the helpless civilian and Buffy pretends to be the superhero that rescues her. But when Der Kindestod comes for Celia, Buffy can do nothing to save her life.

After becoming the Slayer, she meets Der Kindestod again. In order to see him, she purposefully makes herself sick. Buffy does end up snapping his neck, but he leaves a traumatic scar on her that will never fade.

13. James and Grace - "I Only Have Eyes for You"

After suffering a massive heartbreak of her own, Buffy winds up vicariously suffering the heartbreak of a ghost in "I Only Had Eyes for You." James Stanley is a student at Sunnydale High during the 1950s who kills the teacher he's been having an affair with, Grace Newman. Enraged that she wants to end the relationship, James shoots Grace and then himself. Half a century later, James and Grace still haunt Sunnydale High, possessing those who walk its halls so they can reenact their final encounter, all the way to its deadly conclusion.

Buffy realizes that the only way to stop more people from dying is to help James atone for murdering Grace. In a gender reversal for the ages, James possess her body just as Grace possesses her ex, Angel (technically now Angelus, his evil counterpart). Channeling her spirit through Angel, Grace forgives James and the two ghosts are set free.

While neither intended to harm Buffy, James and Grace force her into a seemingly tender reunion with her former lover only to remind her, in a second's time, the true, painful state her love life is in.

12. Ken - "Anne"

Living alone in Los Angeles, Buffy's already pitiful circumstances worsen after she meets Ken. Ken, a demon wearing heavy makeup to disguise as a human, offers shelter to runaway teens roaming LA. In actuality he recruits them to be slaves in the hellish dimension he calls home. Buffy investigates Ken after an acquaintance of her's goes missing, following a trail that leads to his giant horde of enslaved innocents.

To be fair, Ken's defeat finally motivates Buffy to return to Sunnydale. Not the worst impression for a bad guy to leave. However, returning home for Buffy entails rebuilding all the bridges she burned by leaving in the first place. Her mom and friends are all hesitant to trust Buffy after her sudden departure in the season two finale. Ken also temporarily stops Anne, Buffy's acquaintance, from journeying on a road to recovery that goes on until the last episode of Angel.

11. Hans and Gretta - "Gingerbread"

The horror genre is one of Buffy's key influences, and nothing screams horror like a pair of creepy kids. A demon inhabits the bodies of Hans and Gretta Strauss (unsurprisingly the basis for Hansel and Gretel) after the two children die in the 17th century.

In the future, Hans and Gretta play dead in front of Buffy's mother Joyce, leading her to believe their killings were the product of an occult sacrifice. Hans' and Gretta's spirits torture Joyce's mind until she leads a crusade of mothers against perceived cultists, among them Buffy's best friend, Willow.

Aside from fitting comfortably in the horror strands of Buffy's DNA, Hans and Gretta exact some heavy misfortune not only onto Buffy but also her friends. They demonize sweet, wouldn't-hurt-a-fly (for now) Willow in the eyes of her own mother. So much so her mom almost burns her at the stake with a legion of angry moms behind her. Even their group's hilarious name, Mothers Opposing the Occult (or MOO), does little to assuage the terror poor Willow endures.

10. Balthazar - "Bad Girls"

Balthazar has the most revolting appearance of any Buffy villain. He holds sway over his own private cult of vampires, employing one of them to constantly spoon liquid over his moist body while he soaks in a tub of indeterminate substances.

The vampires under Balthazar's command are searching for an amulet that will restore his powers in full. But even without the amulet, Balthazar shows himself to be pretty powerful. He can pull vampires toward him telekinetically and break their necks with his pudgy little hands.

Balthazar is actually the least interesting part of "Bad Girls" because Faith's moral ambiguity upstages his pure menace. He nonetheless holds a spot on this list because of his disgusting looks alone. The Scoobies kill him by way of electrocution, but before dying he spitefully warns them of greater threats yet to come, and promises Buffy she'll wish he killed her.

9. Gachnar - "Fear, Itself"

In the Buffyverse, demons consider Halloween tacky and use it as a night off from havoc-wreaking. Gachnar forgoes this position and turns a frat's haunted house themed party into an actual haunted house. The demon forces Buffy and her friends to face their greatest fears by bringing them to life. Xander becomes unseen and unheard, Oz transforms into a werewolf despite the absence of a full moon, and Willow loses control over her magical powers.

Gachnar loses a lot of points in the end for being the size of an ant, but his frightful display beforehand is still noteworthy. Also noteworthy is his opportune timing. He catches the Scooby Gang at the beginning of their post high school life, a tumultuous time for any new college student (or in Xander's case, current parent's basement inhabitant). If only Gachnar wasn't so darn cute.

8. The Gentlemen - "Hush"

A landmark for the show, "Hush" landed Buffy its first (and sadly only) major Emmy nomination. The episode's success owes a large portion of its thanks to The Gentlemen, a group of creatures pulled straight from Joss Whedon's nightmares and brought to the screen with dazzling effects.

When The Gentlemen descend on Sunnydale, they riddle the town speechless. Literally. Unable to talk, Buffy and friends must find ways to communicate nonverbally. On top of the challenge they place onto the Scooby Gang, The Gentlemen collect the hearts of college students at UC Sunnydale. They need seven hearts in order to kill everyone in the town, and with the townspeople unable to shout for help their job becomes a whole lot easier.

Hovering above the ground as they move, ringing their palms with long grins stretched across their faces, The Gentlemen provide the most harrowing visuals in Buffy's entire run. But in the end, the truly awful crime The Gentlemen commit is forcing Buffy to have a serious conversation with Riley. What couple doesn't dread the inevitable "I'm a Vampire Slayer" talk?

7. Toth - "The Replacement"

Like with Hans and Gretta, Toth stands out for going after not just Buffy but also her friends, in this case Xander. Toth wields a Ferula Gemina and uses it to fire an incantation at Buffy. Xander takes the blow instead, and walks away from it apparently unharmed. However it's soon revealed that he's been split in two. Though both are technically Xander (here played by Nicholas Brendon and his twin), each thinks that only he is the real one, and both are willing to kill the other to prove it. To make matters worse, if one dies, both of them die.

Toth has the scary looks covered. His neon orange skull shines through cracked, mud-brown skin, and his teeth are stained neon green. Scarier still is the Toth's cunning. The Tothric Clan are known for being a more sophisticated class of demon, applying complex tools like the Ferula Gemina to attack mortals.

But really, Toth's dirtiest deed is cutting down Xander's self esteem, which is already at a record low. Feeling insufficient both in funds and as a boyfriend, Xander sees how much better his life would be if he just embraced his more confident self. His mood improves when he becomes one Xander again, though Anya would have preferred both Xanders for one twisted ménage à trois.

6. Queller - "Listening to Fear"

Some might disqualify Queller outright because of his extra terrestrial origins, something decidedly un-Buffy. But those people have to admit Queller's ways are undeniably sinister. A repugnant, shockingly agile slug-like creature, he targets the mentally ill and smothers them with goo he spits from a mouth with multiple rows of sharp teeth. His targets include Joyce Summers.

To add a lacerating insult to a severe injury, Joyce already has a brain tumor that occasionally sends her on sudden, incoherent outbursts. Her rants are so venomous and nonsensical that Buffy is unable to tell when it's the brain tumor's fault and when it's the Queller, sticking to the ceiling of Joyce's room and tormenting her from above. Fortunately, Buffy saves her mother before she chokes on goo.

Up to this point, Joyce has been Buffy's rock, mooring her throughout all sorts of emotional turbulence. But by the time the Queller comes along, Joyce lacks the mental capacity to console or support Buffy, leaving her daughter burdens no teenager should ever have to worry about. Chief among them caring for her little sister Dawn, who's not always the most pleasant person to deal with.

5. Olaf - "Triangle"

And now, a funny one. Olaf the troll has a habit of pillaging lands and an undying craving for babies. That being said, he's one of Buffy's more light-hearted adversaries. Played with jovial aplomb by Abraham Benrubi, it's hard to not keel over every time Olaf goes on goes on a wild tangent about his unquenchable thirst for ale (or when he shotguns several kegs of it).

Anya dated Olaf in the days before she became a vengeance demon. After discovering he cheated on her ("It was only one wench!") Anya puts a spell on Olaf that turns him into a troll. Needless to say, when Olaf comes to Sunnydale he a major vendetta to complete.

Humorous as he is, Olaf is not entirely without evil tendencies. He's breaks from his barbaric rampage for long enough to make Xander choose which person he wants to be left alive: Anya or Willow. Suddenly Olaf stops being fun and games, and presents Xander with an impossible decision between the two most important women in his life. Luckily Buffy, raw from her recent breakup with Riley, puts a beating on Olaf for trying to tear apart Xander and Anya

4. April - "I Was Made to Love You"

Upon creating April, Warren Mears exposed the mysogynistic side of nerdom (a practice that he would sadly carry out until his bitter end). April, a robot invented by Warren with the sole objective of loving him, enters an incomputable situation when Warren begins dating a flesh and blood person. Her programming pushes her to keep obeying Warren regardless, no matter who she might hurt in the process.

Though she wears the appearance of a brunette twenty-something, April is inhumanly strong - Strong enough to hurl a vampire like Spike out a window. However, unlike most of the bad guys on this list, April isn't scary because of some assortment of claws and teeth. She's not even scary exactly, just unnerving because of how she always has a smile on her face and a brightness in her tone.

April ultimately becomes a sympathetic character, revealing Warren to be the true villain of this episode. She was created by a man with the sole purpose of caring for him, and by design feels useless when that man no longer needs him. Pitying her, Buffy remains with April after ripping out her circuitry, sitting next to her on a swing set as she powers down. It's one of the rare quiet moments Buffy shares with an opponent.

3. Sweet - "Once More, With Feeling"

Another landmark episode for Buffy, "Once More, With Feeling" propelled Buffy into the musical genre. Sunnydale comes under a curse that causes its citizens to break into song and dance at the most unpredictable moments. At first this phenomenon doesn't seem like that much of an issue, until people start dancing their way to spontaneous combustion.

Sweet is the monster behind all of this, a tap-dancing devil with a smooth jazz singing voice. He comes to take Dawn away to his kingdom and make her his Queen, which Dawn points out is kind of illegal. When he find's out Dawn is Buffy's sister, he adjusts his plans slightly so he can watch Buffy burn in front of him.

What makes Sweet so scary has less to do with how he looks and more about his cock-sure manner. He always seems ahead of the game, on top of the situation. Sweet is actually the only villain on this list who arguably defeats Buffy. He departs without Dawn and releases Sunnydale from his curse, but he leaves Buffy and her friends with some hard truths to address. And he does it with a spring in his step and a song in his heart.

2. Glarghk Guhl Kashmas’nik - “Normal Again”

What if everything that's happened to Buffy is product of her imagination? Thanks to suspension of disbelief, viewers know this to be false. But when Buffy is teased with the notion that her reality is fantasy, it doesn't seem unreasonable to her.

This is the wrath of Glarghk Guhl Kashmas’nik, a demon summoned by a didgeridoo (yeah, a didgeridoo) to put Buffy through mental turmoil. Equipped with arms that shoot out spikes, one of these Whatchamacallits (not typing it again) inject a poison into the Slayer that makes her think she's in a mental hospital. She's convinced by apparition of Joyce, who is not only alive in this world but also still with Buffy's father, that all the events in her life, from the spells to the apocalypses, are total fiction.

Buffy warms to the idea that she isn't a Slayer, but instead a disturbed girl with delusions of the supernatural. Not only does she start to believe it, she also starts wanting to believe it. She acknowledges it would be easier to abandon her tenure as Slayer and indulge a simpler existence. The demon (still not typing it again) is evil for making Buffy think she's crazy. But he's downright diabolical for making her want to stay that way.

1. Gnarl - "Same Time, Same Place"

Season seven devoted most of its time to the First Evil and the potential Slayers, so there wasn't a whole lot of room for one-off villains. Fortunately, seasoned Buffy writer Jane Espenson gave us "Same Time, Same Place," an episode that showcased an insidious beast called Gnarl.

Gnarl rolls into Sunnydale around the same time Willow returns, having spent time in London amending for her recent bout with dark magic. As soon as Willow arrives, Buffy and the rest of the Scooby Gang find a flayed body at a construction site. They suspect the body is Willow's doing, since she did the same to Warren when she was consumed by dark magic.

It's ghastly enough that Gnarl eats human skin and has the ability to paralyze the objects of his appetite. But what solidifies him as a memorable villain in Buffy's long roster is how he adds to the distance between Buffy and Willow, which became Grand Canyon-sized after their final battle in season six. What was once an iron-clad friendship has become a more fragile relationship, and Gnarl's wicked plot almost obliterates it entirely.

Buffy the Vampire Slayer is on Netflix until April 1st.