Cardi B dressed up like a sexy nurse, because it's a classic for a reason.

Hello, nurse! "I’m here to assist your shhhttaaaankin ass," Cardi B wrote on Instagram. She stuck with the tried-and-true sexy nurse costume, complete with slick red latex tights and a stethoscope. But it's that waist-length fire-engine red wig that truly completes the look. 

Stormi Webster dressed up as her mother, Kylie Jenner.

In a sentence that could only be written in 2019, one-and-a-half-year-old Stormi Webster dressed up as Kylie Jenner at the 2019 Met Ball. Jenner wore a custom lilac Versace thing covered in feathers, and now Stormi has stolen her look. What a world.

Halsey's spin on Marilyn Manson nails it.

Halsey transformed into noted blasphemous shock-rocker Marilyn Manson, and I must say, this one is a winner. The look comes from Manson's 1998 album Mechanical Animals. True story: Halsey loves Manson so much that she has a tattoo of him on her ribcage.

She also dressed up as Cher and it is gorgeous.

"Been dying to try out a good @cher makeup forever and finally got to!" Halsey wrote on Instagram, and I agree. That Cher makeup is too perfect, right down to the crystal waterline and fake lashes that reach into the sky. Can you believe?

Nicki Minaj and beau Kenneth Petty went as a couple of Suicide Squad members.

Regardless of what you think of the Suicide Squad movies (and folks have opinions), there's no denying that Nicki Minaj and her new husband Kenneth Petty nailed their respective Harley Quinn and Joker costumes.

Kourtney Kardashian fully dressed up as a Victoria's Secret angel.

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Kourtney Kardashian worked the imaginary lingerie runway in her Victoria's Secret angel look, complete with suspender garters and giant wings. 

Kardashian also brought down the house in her homage to Ariana Grande.

Celebrities dressing up as other celebrities will always be funny — and Kourt's Ariana Grande costume proves that there are no more tears of hilarity left to cry. Kardashian truly captures Grande's massive eyeliner wings and signature high ponytail like a master.

Gabrielle Union did it. She definitely did it.

Yes, Gabrielle Union wonderfully trolled us all in her costume of  ...  herself. Or rather, her costume from her Bring It On character, Isis, the take-no-nonsense cheer captain of the East Compton Clovers. Don't even try to steal her routines.

Bachelor alum Nick Viall, never not being self-referential.

Nick Viall, a former Bachelor, dressing up as Pilot Pete, the upcoming Bachelor, is so meta, it may be as well be a snake eating its own tail. Viall hilariously even captured Pete's mysterious injury that caused him to be treated with facial stitches.

Nina Dobrev hopped on one of 2019's biggest costume-trend trains.

Another case file in the celebs dressing up as other celebs. This time, Nina Dobrev copped Billie Eilish's teen mall goth look, oversize clothing and all. The wig, sporting her neon green roots, is particularly impressive, as is the jangle of Louis Vuitton accessories.

Reigning Halloween champ Heidi Klum did it again.

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FIREWORKS ???? ????❤️????

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Still, no celeb does Halloween like Heidi Klum. Every year, she dazzles, and this year is no exception. She dressed up as a fireworks display, covered in so much glitter she can be seen from outer space. I am despairing for her bathtub.

Dazed 100 winner and plus-size model La'Shaunae Steward took it right back to MySpace days.

Let's get freaky now! La'Shaunae Steward paid homage to everyone's emo scene days with this hilarious getup, dedicated to "crunkcore" band BrokeNCYDE. She even got the beaded bracelets just right. We don't blame you if you feel the need to go take a pouty selfie.

Kylie Jenner dresses up as sexy mermaid Ariel because of course.

Kylie Jenner is never not extra, whether she's wearing her own costume or dressing up baby Stormi as herself. In her first Halloween costume, Jenner dressed up as Ariel from the Little Mermaid ((if Ariel was in an R-rated flick). The shell bra made of actual shells is impressive.

For her next costume, Jenner channeled another sexy icon.

Ariel wasn't Jenner's only costume. Next, she dressed up as Marilyn Monroe, complete with opera-length gloves and piles of diamonds. Given that Jenner is a billionaire, it's very possible that her costume jewelry is diamonds. 

Big sis Kim Kardashian came through as Elle Woods.

Kardashian is studying to become a lawyer, so her Legally Blonde costume is especially on point. But her take on Elle Woods is decidedly sexier, with a pink plunging silk minidress and a new wavy 'do. Most important, where did she get that dog, and can I pet it?

Ciara is probably the only person who can pull off Beyoncé, except Beyoncé.

Ciara and husband Russell Wilson did not come to Halloween to play, they came to slay. The couple dressed up as Beyoncé and Jay-Z in their iconic Mona Lisa photo. But instead of Da Vinci's mysterious lady, Ciara and Wilson stood in front of a photo of Barack and Michelle Obama. Excuse me while I set this photo as my phone background.

LeBron James dressed as another king — the king of goth flicks.

Los Angeles Lakers player LeBron James dressed up as Edward Scissorhands, a costume that lots of people attempt but few actually accomplish. Leave it to the GOAT to slam-dunk this costume. His wife, Savannah James, came through as Aaliyah as Akasha, Queen of the Vampires from Queen of the Damned.

Tallulah Willis went for another Halloween classic.

Leeloo, as portrayed by Milla Jovovich in the Fifth Element, appeared in another modern-day Halloween classic. Tallulah Willis captured Leeloo in the scene where she's trying to fall off a building, and we love this sci-fi throwback.

Fun fact: Leeloo's full name is Leeloominaï Lekatariba Lamina-Tchaï Ekbat De Sebat. You can call her Leeloo Dallas Multipass for short.

Ariana Grande went for real creepiness.

Grande decided to spook us out in that unsettling, uncanny way that only the Twilight Zone can. She's wearing a pig mask, made famous by the "Eye of the Beholder" episode, in which a woman's cosmetic surgery procedure goes horribly wrong. Eeek!

Kevin Hart as Dwayne "The Rock" Johnson had us SCREAMING.

That's it, Halloween is over, everyone can go home. Kevin Hart just won Halloween 2019 with his Dwayne "The Rock" Johnson costume, except Johnson as a meme. He even accessorized with the fanny pack, silver chain, and most essential, the crumbled napkin under his elbow. What is that napkin about? The world will never know.

Kim Kardashian West took the family for their annual Halloween photo.

In her next appearance on this list, Kim Kardashian wrangled together the Kardashian-West clan for a Flintstones-themed family photoshoot. The costumes themselves are hilarious and adorable, but what is truly truly terrifying? That very obviously photoshopped Chicago West, who is crying and upset in the corner. 

"This family pic was such a challenge because Chicago was so scared of Dino! LOL We tried to explain and show her that it was just daddy but she didn’t get the concept yet!," she wrote on instagram, but I would like to know why she was photoshopped into looking halfway-normal. Family photos are even better when one baby member of the fam is in a full-on tantrum.

Apparently when you are a celebrity, you are expected to have multiple costumes.

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You can have your space, cowboy.

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Not to be outdone, Kourtney Kardashian enters this list again with space cowboy costumes. She's twinning with pal Stephanie Ann Shepard, and both of them are decked out in silver shorts so tiny, I feel a vaginal infection coming on just looking at them.

Does Kourtney have a separate wardrobe just for Halloween?

It's Kourtney, again. I promise, this is the last time Kourntney shows up again in this post. Here's she's channeling Morticia from the Addams Family, and she's kind of killing it? No pun intended. Whoever did her makeup deserves an award.

The Flintstones must have been popular this year.

This year, Bella Hadid sexed up the decidedly-unsexy Fred Flintstone. Her loincloth is the tiniest, her blue tie is the skinniest, and her makeup is the stunning-est. Were the Flintstones a big Halloween 2019 trend, and I just missed it somehow?

Gigi Hadid took it in the exact opposite direction.

If Bella went sexy, Gigi Hadid went full-on unsexy in her Mask outfit. Not only is she unrecognizable in the makeup and green face makeup, but every time I see the Mask, I hear Jim Carrey's voice in my head, which is the least sexy thing ever.

Cardi B is killing us softly!!!

Hello, 911? Excuse me, yes, I would like to report a murder, because Cardi B has just stepped on my neck with her poisonous leaves. Poison Ivy has never looked so good, and frankly, this super villain could destroy you with that hair alone.

Adam Rippon was Lizzo's flute! THE CREATIVITY AHHHH

I have no "100% that bitch" jokes about Olympic figure skater Adam Rippon's costume, just pure unadulterated bliss. He's Lizzo's flute, you guys. LIZZO'S FLUTE. Which is totally not a gimmick, by the way — Lizzo has played flute since elementary school, and studied flute performance in college.

As for Lizzo herself, she became the titular character from her own song.

In her song "Truth Hurts," Lizzo took a DNA test, and the rest is history. For Halloween 2019, Lizzo decided to dress up as her own DNA test, which is so beautiful and pure, I want to play this video on repeat forever. She arrives at a door as a box, comes complete with a DNA swab, and opens to reveal the results. Yes, 100% that bitch, scientifically proven.

Neil Patrick Harris and his family took us back to Art History 101...

Neil Patrick Harris, David Burtka, and their two children Harper and Gideon, were decked out in masterpieces — literally. They are dressed up as famous artists: Frida Kahlo, Salvador Dalí, Andy Warhol, and Vincent Van Gogh.

...and later, Harris and Burtka took us to the mean streets of SoHo.

In what is probably my personal favorite celeb Halloween 2019 costume, Harris and Burtka dressed up as the Olsen twins. IT'S. SO. PERFECT. Their makeup captures that sharp Olsen countouring, and they're even smoking, wearing long black clothes, and carrying clutches. We have no choice but to stan.