Katy Perry, like most of us, can't resist a Flamin' Hot Cheeto.
Per her norm, Bey looked fierce channeling Janet Jackson with daughter Blue Ivy, er, Michael Jackson in tow.
In a play on the lyrics from her song "Blank Space" from 1989, Swift said of her costume, "Cause, darling I'm a nightmare dressed like a PEGACORN."
On The Ellen Show, Scandal actress Katie Lowes showed off her creative tooth fairy ensemble while Ellen rocked her own clever costume — George Clooney's wife, Amal Alamuddin, complete with a cardboard-faced Clooney, natch.
Kate Hudson as a Sons of Anarchy-inspired leather-clad biker chick, in case you were wondering, looks dangerously hot.
Is it too soon to say Queen Latifah's elaborate Maleficent costume is our favorite spooky getup this year? 'Cause we are definitely under her spell.
Liv Tyler, who has a bun in the oven, dressed as a retro oven with a bun in it. Tyler's might just be the most adorable celebrity maternity costume ever.
Kelly Osbourne doesn't take her legacy as the daughter of the "Lord of Darkness" lightly. This year, she slayed as Magenta from The Rocky Horror Picture Show at her themed party...
and later as Margot Tenenbaum, aka Gwyneth Paltrow's character from the 2001 movie The Royal Tenenbaums.
If we were roaming the halls of our office building like Lucky's editor-in-chief, Eva Chen, and ran into these two, we might have needed to take a few sick days. The Shining's "Redrum" twins came courtesy of the mag's creative director, Katia Kuethe, and features editor, Hayley Phelan.
Inspired by American Horror Story's controversial "Spooky Little Girl" episode, Michelle Trachtenberg creeps the hell out of us as The Black Dahlia.
Pregnant Molly Sims get major style points for going "pregogogo" in a '70s-inspired hot pink jumpsuit...
and gets bonus points for then getting decked out as Snow White to take her little Batman, 2-year-old son Brooks, trick-or-treating.
Is Minnie Mouse the most original costume of the night? No. Not even close. But you've got to admit socialite Paris Hilton looks gorgeous as a grown-up version of the iconic Disney character.
As Saved By the Bell's Zack Morris, Kelly Kapowski, Screech, and Jessie Spano, the Live from E! hosts made our inner adolescent hearts skip a beat.
When it comes to most remarkable transformations, Teen Wolf actor Colton Haynes might just have that title in the bag as Fiona from Shrek.
While his alter ego likely won't be too pumped about it, Chris Colfer's Grumpy Cat costume made us especially happy. Or should we say Glee-ful?
Pretty Little Liars' Lucy Hale and guy pal Drew Osborne went digital, dressing as Twitter and Instagram, respectively.
Fashion fanatic AnnaLynne McCord left little to the imagination as the "Creepy Chick" muse to her fabulous companion's Karl Lagerfeld.
Nothing could be sweeter than Red Sox pitcher Drake Britton sporting a Superman costume to bring Halloween cheer to kids at Boston Children's Hospital. Hmm, perhaps it isn't a costume at all.
Jessica Alba came to rock this Halloween! She and a gal pal went all-out as Axl and Slash of Guns N' Roses fame.
No ifs, ands or bones about it — Kim Kardashian makes one sexy skeleton.
It wouldn't matter if Kim Kardashian and Kanye West's daughter North was smelly like a skunk — she'd still be as cute as all get out.
Hockey pro Brooks Laich and Dancing with the Stars judge Julianne Hough looked groovy, baby, as Austin Powers and Felicity Shagwell.
What does a woman who basically lives in outrageous costumes for a living do on Halloween? Well, if that woman is Lady Gaga, she glams it up in an elegant Roberto Cavalli flapper costume.
This family could not possibly be any more adorable. Neil Patrick Harris, husband David Burtka and the couple's precious twins Gideon (Batman) and Harper (Batgirl) went Gothan City chic.
Pretty Little Liars' Ashley Benson was undoubtedly going for creepy with her supernatural Annabelle doll look, but we can't help but notice how stunning she is.
Joe Jonas as Derek Zoolander is perfection. That is all.
For his first time trick-or-treating, we think it's safe to say Josh Duhamel and Fergi's son Axl Jack — or "Daddy's lil stinker" — nailed it. And, um, they need to do the world a favor and set Axl up on a play date with North West ASAP.
Yowza. This ain't the Little Red Riding Hood of your childhood, people. Glee's Lea Michele opted for a decidedly more adult version of this classic character.
As the self-proclaimed "King of Harlem," Diddy strikes a regal pose alongside his trumpeters.
Meanwhile, Diddy's daughter Chance looked flawless as Cleopatra. The gorgeous little girl vogued it up for her dad's Instagram account, even walking like an Egyptian.
First of all, we respect anyone who appreciates cozy coverall costumes as much as we do. And, second, it's pretty darn adorable that Rumer, Tallulah and Scout Willis (or a sloth, a seal and a flying squirrel) skipped the crazy festivities to stay home and watch scary movies together instead.
Donald Faison and Cacee Cobb threw it back 3-D style with this incredible King Kong costume.
We love it when pretty girls aren't afraid to get a little ugly. Amanda Seyfried and celebrity chef Vikki Krinsky embraced the dark and undead with zombified face makeup.
Just when we thought we couldn't possibly adore The Biggest Loser's Bob Harper any more, he busted out a spot-on David Bowie costume this Halloween.
Leave it to celebrity stylist Rachel Zoe to pull together super-stylish Halloween ensembles for her whole cute family, which apparently includes a princess (Zoe), Captain Hook, Peter Pan and a lamb.
Can we just say meow? Dressed as a sexy kitten, Victoria's Secret model Allessandra Ambrosio looks, well, sexy. And like a kitten.
In case you needed any further evidence that Zach Braff is brilliant, we give you his Halloween costume of Kurt Russell from Big Trouble in Little China. Bonus: He actually ran into the real Kurt Russell while out and about. Best Halloween ever?
Modern Family's Jesse Tyler Ferguson and husband Justin Mikita crack us up as Lloyd Christmas and Harry Dunne from — what else? — Dumb and Dumber.
If this is what being "under the sea" looks like, count us in. Victoria's Secret model Adriana Lima donned an emerald-hued mermaid wig to complement her daughters' Ariel costumes. Lima's ex-husband, Marko Jaric, rounded out the Little Mermaid family as Triton.
Ryan Seacrest looked electrifying as as an Albert Einsten-esque mad scientist.
Mad Men actress January Jones got cheeky with a little friend as "#hashtag Christmas tree." Dare we say we're mad about clever costumes like this?
Dressed to the nines as The Green Lantern, funny guy Colin Hanks jokes that he may as well put the costume to good use — since he's still waiting on that callback audition for the part.
She might not be the "California Gurl," but Carmen Electra does a pretty fantastic job of channeling Katy Perry for her SVEDKA Vodka Halloween Party.
Gisele Bündchen and Tom Brady let their 4-year-old son choose the family costumes this year, and they ended up as a brood of dragons. Really, really cute ones.
Hey, Justin Bieber actually put on a shirt for Halloween, so we think that's kind of a big deal. Besides, it's sweet that he dressed up as a Power Ranger to please his little buddy.
Supermodel Cindy Crawford and husband Randy Gerber hit a high note as Cher and Greg Allman.
Kaley Cuoco and hubby Ryan Sweeting as the Biebs and his on-again-off-again girlfriend Selena Gomez may ruffle the fans of a few Beliebers, but we're impressed. I mean, who knew Cuoco would make such a lookalike Bieber?
Heidi Klum never disappoints on Halloween, and this year was no exception. Here, the star shares the behind-the-scenes insight on how she was transformed into a butterfly of epic proportions.
DIY queen Lauren Conrad got into the Halloween costume game by whipping up her very own mermaid outfit. And, really, who wouldn't want to wear this shell-adorned masterpiece?
While Gwen Stefani hit up Kate Hudson's Halloween bash with husband Gavin Rossdale as a pair of vampires, the Voice judge rocked a fierce tiger costume on Halloween day.
We love all things Orange Is the New Black — which now includes Kelly Ripa and her Live with Kelly and Michael crew as Piper, Crazy Eyes, Red and Alex.
Jenny McCarthy and this throwback Sandy from Grease costume go together like rama lamma lamma ka dinga da dinga dong.
Someone put this man in a horror movie, STAT! Adam Lambert is terrifying (and terrifyingly hairy) as a werewolf headed to "howl at the moon."
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