Hilary Duff Defends Mouth-Kiss Instagram Photo With Her Young Son

Third from the left. Guests ranging from Ice-T and Coco (a psycho inmate and a referee) to Hannah Storm (an outstanding Lucille Ball) swarmed Vandal in NYC, where  Svedka flowed from the bars.

Heidi and clones arrive in a box. 

Celebrities dressed as other celebrities are always score.

WINNER: Courtney Mazza and Mario Lopez stepped right out of "Saturday Night Fever" at the Casamigos bash.

WINNER: Tom Cruise, is that you? Nope. It's Zach Braff who feels the need... the need... for speed! 

WINNER: Whoever these guys are (because we really don't know), invite them back next year. This anonymous battalion of G.I. Joe figures is an "only in Hollywood" costume. 

WINNER: Zedd as Daft Punk. Period.

WINNER: Cindy Crawford, host Rande Gerber, and their kids Presley Walker (left) and Kaia Jordan Gerber as the "Sex Pistols."

JUST OK: Robin Thicke and April Love Geary as Julia Roberts and Richard Gere in "Pretty Woman."

JUST OK: Seth MacFarlane as Oscar the Grouch. The bon vivant gets points for not trying to upscale on "cool" (see: Zach Braff above) and keep a lower profile at the busy bash. But I expect more from one of the most creative and quick wits in town.

FAIL: L.A. Clippers Coach Doc Rivers and David Spade. Hey Spade, you have to at least try. Being a celebrity is not enough cache for the Casamigos party.

JUST OK: Russell Simmons dusts off one of his stock costumes: dressing up as his brother Rev Run's group Run-D.M.C.

Simmons repeated the costume the next night at Steve Shaw's treats! magazine party. 

PAR for the COURSE: Stacy Keibler, who used to date Casamigos co-founder George Clooney, is still on the "it" list. With Kiebler, Emmanuelle Chriqui and Jenna Dewan Tatum (as a unicorn).  

FAIL: Kevin Connolly (center) took the same approach as his fellow frequent social-scenester, David Spade. "Gilligan's Island"-themed costumes are rare, but easy.

GOLD MEDAL: Ryan Lochte is good at swimming, bad at lying and surprisingly swift at costume design. In the male division, he tried the hardest, and it shows.

WINNER: Ryan Lochte himself proved to be celebrity costume-worthy. Nina Dobrev and pal Lane Cheek (a prop master on "The Vampire Diaries") "stripped down" to portray scandalous swimmers Lochte and Jimmy Feigen of the Rio Olympics "gas station incident" at Matthew Morrison's event.

B+: Kelsey Grammer plays "Sideshow Bob" on "The Simpsons," so although he picks low hanging fruit, the meta joke and obscure pop culture reference nudges him towards win territory.

JUST OK: Sly, this "get-up" is acceptable for a costume party in April. He gets extra credit for "relevancy" if he was attempting for a "Westworld" reference. Because he's Sylvester Stallone coming out to Hollywood parties, which is a rarity, his presence saves this from the fail-zone.

COSTUME IN A BAG FAIL: Ryan Seacrest. Guilty. Moving on.

COSTUME IN A BAG FAIL: James Corden. The late night host and wife Julia Carey look like they got in a fight on the way to the party. 

B: Andy Garcia's professional makeup amps up his "Day of the Dead" persona.

JUST OK: Good to see you out and about, Lauren Conrad. But I can't tell if you're playing into character as a sad ballerina doll or just in default humdrum LC mode.

B: Brian Grazer and teenaged-son Thomas pay homage to cult film "Donnie Darko." Like Kelsey Grammar, they got creative in concept but their execution is uninspired.

FAIL: King Bach. I'll cut him some slack because of the news that Vine, the platform that made him famous,  is shutting down.

Also Read: #RIPVine: Twitter Shutdown Creates Loop of Despair

FAIL: Larry David. Is this a bit? Is this part of your schtick? Odd that both David and MacFarlane, two of the most brilliant comedy minds, have the same Halloween blind spot.

FAIL: Jeff Probst. What is this? Minus the mask, these threads probably hang in his closet and he could wear them to the Emmys.

WIN: Harry Hamlin and Lisa Rinna as Sonny and Cher. They are both try-hards, which pays dividends in this contest. 

MASK IN A BAG FAIL: Kenneth Cole. He has an excuse. As Chairman of the Board of amfAR, Cole raised more than $2 million the night before for the cause at an event honoring Jeffrey Katzenberg and Charlize Theron. 

Meanwhile at the bar: "Bloody Great Margaritas," "Spirit of the Night" cocktails, and wood fire pizzas, tacos and french fries were passed through the party. 

Developer Mike Meldman (right) is a partner in Casamigos with Gerber and Clooney. Although it's unclear what his  costume is (Jay Z?), out of deference for a great party, I reserve judgement.

JUST OK: Model Charlotte McKinney is dressed as if she's going to one of Gerber's former hotspots, the Skybar. 

B+: Tara Reid remixes the holiday calendar as the skinniest Santa at the Treats party, which had top-tier party partner Absolut Elyx on board.

Jared "Just Jared" Eng's Halloween party owned Sunday night, October 30th. Flexing- both his pull and his muscles - the media entrepreneur had Miles "Gene Simmons" Teller (WINNER) amongst the crowd that included Georgie Flores, Leona Lewis, Keke Palmer, and J.J. regular Ariel Winter.  

WINNER: Manager Eric Podwall as Bela Karolyi, complete with hired extras playing young gymnasts.

WINNER: Kevin McHale as retired Celtics great Kevin McHale.

WINNER: Matthew Morrison as Jared Leto's "Suicide Squad" joker. This group huddled up at Morrison's Halloween/Birthday party at Hyde on Saturday night, October 29. 

B+: J.C. Chasez gets bonus points for being Andy Warhol at a celebrity party, as the late artist frequently photographed his contemporaries' events. Forty years ago, Morrison's bash with Freixenet would have been on Warhol's docket.

A-: Rebecca Rittenhouse and Chase Crawford channeling Gwyneth Paltrow and Luke Wilson's "Royal Tenenbaums" characters at Morrison's.

A: Bryan Singer proves why he's a top tier director by delivering a complete court for his Egyptian pharaoh look: He cast and styled a supporting cast for himself, while his own threads look tailored. 

FAIL: Randy Jackson often chooses loud gear. We can't tell if he dressed up in a Alvin's varsity letterman jacket from Chipmunk High, or just stopped by the Treats party after a non-Halloween dinner. Treats ringmaster Steve Shaw nested with the theme, dressing Dracula-esque for the cathedral style design of the bash in downtown L.A.

WINNER: Emily Ratajkowski as Cleopatra in Brooklyn, leaning in to type. Ratajkowski posed here on the VIP balcony at Bacardi and Kenzo Digital's Haunted House, "We Are the Night", a private bash where Mark Ronson and Swizz Beatz performed on Saturday night, October 29.

B: Mark Zuckerberg and wife Priscilla Chan shared this pic of their baby girl Max's first Halloween. "A family of vikings, a sheep and one adorable little dragon," the Facebook founder posted. The sheep dog gets an A. The Zuckerbergs lose a half point for the Ugg boots. Do the Zuckerbergs "actually get trick or treaters and pass out candy?" a commenter asked.  "Yes, it's a lot of fun," Mark replied.

They’re currently dominating on "Dancing With the Stars," but it was all play for IndyCar racer James Hinchcliffe and his pro-partner Sharna Burgess at the 2016 MAXIM Halloween Party. Throwing back to the '80s in matching "Top Gun" costumes, the pair looked just as cool as they do on the ABC reality contest as they sipped on cocktails by CÎROC Mango, Tequila Don Julio Blanco and Don Julio 1942.

Chris Brown dressed up as a... a... no costume necessary! Brown was a guest rather than a performer at the 2016 MAXIM Halloween Party, produced by Karma International at the Shrine Auditorium on Saturday Oct. 22. DJ Vice gave the singer a shout out from the decks, as guests got to explore the haunted playground designed by creative director Ryan Patterson.