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The adorable dog mama, dressed up as a skeleton, spent some quality time reading Halloween literature to her golden retriever, Birdie. (But is the witchy pup enthralled by the book or passed out?) This is Garner's second Instagram edition of #BooksWithBirdie.
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REESE WITHERSPOON (AGAIN!)
Meanwhile, Reese's Frenchie Pepper went as everyone's favorite "French" fast food.
"I don't know about y'all, but I prefer a little Pepper in my #FrenchieFries! #PepperPortraits #PepperPoses #HappyHalloween," the actress posted.
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The Game of Thrones star's real-life "direwolf" is a little fluffball named Sonny, who appeared to be decked out in a lion's mane for Halloween ... or is he just cold because winter is coming?
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Self-proclaimed "crazy dog mom" Schumer dressed her little pup Tati up as an adorable purple octopus.
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"Happy Halloween from Norman the lion, Wonder Woman shirley shark, and Ruby the mini jester," posted the Big Bang Theory actress on her dog Norman's Instagram account.
Not pictured is Kaley Cuoco herself, but she did include a shout-out to @the_pet_handler "for making me cry with laughter waking up to this!"
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The Orange Is the New Black star dressed up one pup (seen here) as a witch and another as a pumpkin.
"Mean as witch and her pumpkin ... bapadi, bapadi boo #Issawitch #issajackolantern #Rainbow #Cash," posted Polanco.
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President Mellie Grant went the Pulp Fiction costume route, while her pup ended up as an exhausted little hotdog.
"A big #Halloween tuckered somebody out. Hope everybody had a fun day! Sending you all so much spooky love!" the actress wrote.
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Young's dog Bean wasn't the only hotdog in the Hollywood Halloween cart: Lumpy's costume was also quite a treat!
Sofia Richie Cuddles Up with Her Adorable New Puppy: 'How Are You Real?'