Halloween officially falls on a Monday this year, but with most adults holding their costume parties on the weekend before, the internet has already been flooded with creative, spooky and hilarious getups.

Here's a look at some of the very best costumes making the rounds online.

Internet still chewing on dog-lover's costume

Video of a man dressed up as his dog's favourite chew toy went viral over the weekend, racking up an incredible five million views in its first four days. It was the No. 2 trending video on YouTube by Monday morning.

The video shows a golden retriever reacting to its owner's giant Gumby costume. The dog leaps all over the man, paws at his body and eagerly licks his face.

Celebrities

Actor Kelsey Grammer may have had the funniest costume of the year. Grammer painted his skin yellow and donned a golf shirt and a spiky wig to go as Sideshow Bob, the evil character he provides the voice for in "The Simpsons."

Katy Perry dressed up as a convincing Hillary Clinton for Halloween, while boyfriend Orlando Bloom sported a creepy but not-as-convincing Bill Clinton getup.

Hockey star P.K. Subban nailed it as Prince for Halloween, while boxer Floyd Mayweather dressed up as the "richest superhero," Iron Man.

 

If I'm going to be any superhero, I have to be the richest superhero. #TonyStarks aka. #IronMan #Halloween2016

A photo posted by Floyd Mayweather (@floydmayweather) on

With most major celebrity parties held over the weekend, social media was flush with famous people in costume.

 

Happy Halloween ������

A photo posted by Demi Lovato (@ddlovato) on

 

Diiiiiirty @xtina

A photo posted by Kylie (@kyliejenner) on

 

Stranger things #happyhalloween from Eleven and Dustin!

A photo posted by @amyschumer on

Hilary Duff and her boyfriend raised the ire of the internet over the weekend with their culturally insensitive couple's costume. Duff dressed as a short-skirted pilgrim, while her boyfriend, Jason Walsh, donned war paint, a feathered headdress and a deerskin outfit as a Native American warrior.

Hilary Duff costume

Amid a wave of backlash over the outfits – particularly Walsh's costume – Duff took to Twitter Sunday to apologize. "I am SO sorry to people I offended with my costume," she wrote. "It was not properly thought through and I am truly, from the bottom of my (heart) sorry."

Walsh also apologized through his Instagram account, saying he "meant no disrespect" and would not have repeated the decision in hindsight.

Creative makeup

Most celebrities have the luxury of hiring makeup artists and stylists to design their costumes. However, a few non-famous Reddit users managed to pull off some top-notch looks for Halloween, using nothing but their own incredible makeup skills.

I was an acid trip for Halloween from pics
Cracked doll makeup from pics
Pregnant Cartman from pics

Pumpkin fun

While most of the excitement surrounded costumes, some people got into the Halloween spirit with creative takes on the tradition of pumpkin carving.

Canning jar lids
Gf first attempt at carving pineapples (they sold out of pumpkins)
The store ran out of pumpkins but I didn't want to be left out